Returning for a moment to the 'good instance-bad instance' discussion.

The linear vs. non-linear discussion is a bit of a misnomer in my opinion, and is more accurately described as interactivity vs. non-interactivity. Making a 'non-linear' dungeon is just one of the more obvious and simple ways of making it interactive.

A lot of the dungeons people consider 'the best' are extremely linear. What makes them good is the fact that you they are grounded in the game: The player has a reason to go, the boss has a reason to die, and the environment has a reason to exist beyond loot pinatas. You're collecting keys to advance, blowing down doors with cannons, sneaking in through the sewers to get inside instead of walking in the front door, moving a storyline forward, or battling through waves of enemies while being under fire in gauntlet-style events. Non-Linear dungeons are tagged with this because they give the player a sense of exploration, as if they are in a real environment rather than a long hallway. The core mechanic, however, is that the player is an active participant in the instance, making it so that the world of the instance itself feels changed after the player moves through more than just having all the dudes that were waiting around in groups of 3 and 4 are now dead.

Take Mana-Tombs for example, often considered one of the worst, if not the worst, instances in TBC. The main quest involving that instance is that the Consortium wants to get inside to nab all the goodies. Right now, you clear to an arbitrary point, hit a doodad, and suddely having the consortium teleport in, meander around, and do nothing of value.

Now picture that you instead had to activate multiple portals around the zone, which then ported in Consortium mobs that would fight alongside you, give you buffs, or change the instance map in some other way. The player is now actively changing the world of the instance, rather than passively moving through it. A boring instance suddenly turns into an interesting one.

Why are the CoT 5-mans often considered the best of the expansion? I would posit it's not because they are outdoors (although that helps.) Instead, its because by the end of the instance, you've *changed* the instance itself (rescued Thrall from prison or saved Medivh.)

This neatly ties in with all the discussion before about linearity. Not only is the instance layout on both pretty linear, you don't even get to decide on the size or pace of the pulls, it's all hard-coded. Yet, because there is a clear motivation and context for both instances, the linearity is completely forgotten.

This one of my favorite aspects of TBC, Heroics were very hard and challenging. They were living up to the title of "Heroic", while now a days pretty much every instance you do is assumed to be a Heroic (even for rerolls that just hit 70) and they are pretty easy. Part of it was the gear level, but a lot more of it was the huge nerf heroics got in a patch. Doing the pre nerf Heroic Shattered Halls timed event for TK attunement is the fondest memory I have of any 5 man instance.

I also liked how there were essentially tiers of heroics, Underbog and Slave Pens could be farmed pretty easily once you were able to clear them. While the same group that could clear Underbog in less then an hour might not be able to finish heroic Shattered Halls. It gave you something to work towards and show off your skill. Heroic Durnholde was a great example, which was one insanely difficult heroic when TBC came out. I remember it took me and a group of 5 people almost a week to finally complete it, since you could only wipe 3 times, while with same group we could blast through Underbog/SP easily. When we finally did cleat it, it was a great feeling. Knowing we were the only people on Horde at the time who were able to clear this heroic.

The main problem with how Heroics were is how you overcame the difficulty, which normally involved stacking of CC (particularly Mages). Blizzard seems to realize that, and should be something to easily balance around. Just have very few mobs susceptible to CC, and balance it around that. Another problem was the lack of item rewards, with gear that was generally on par with normals. If you did instances just based on rewards then a lot of heroics sucked.

I really hope that when I hit 80 that LK heroics will have the same difficult feeling that they did when I first hit 70, and not just become the de facto instance type after a couple weeks.

Biggest problem I had - and still have - with heroics, is that most of 'difficulty' is just higher numbers. There's no creativity in making stuff hit twice as hard, except straining healer and making it more punishing to go there without CC. You are still running the same instance you did before, same mobs, same bosses, same drops for lvl70 instances. Worse, bosses were often exactly the same as on normal, and quite often you wondered, if they just 'forgot' to tune them, as trash was far more dangerous compared to them.
What I'd prefer is something like Murmur/Mechano Lord - new mechanics not present on normal mode, making it feel at least a bit different. Sure it will all be the same after you farmed it several times for Badges, but even simple change gives a bit of fresh air to old instance. Maybe adding some new mob types to pulls, etc. 1 new skill per boss - even if it's just for final one - would help a lot.

Since we aren't fixing Wrath here -- the die is cast, and largely from what I've been told in a direction i'm not very excited about -- it's worth recognizing something about the instances that is beyond the game designer's control. I'm fairly sure my very first Botanica run took on the order of 2+ hours -- in normal mode, with solid WoW players. By the end, in badge/tier 5ish gear, my groups could do heroic in ~30 mins. Part of that was due to the nerfing of the instance, part of it was due to massive gear growth from a mix of quest blues and greens (personally, I dinged 70 on my characters in Terokkar and BEM, so it's not like I tended to have the best quest items anyway).

I think most of us agree that originally a few of the instances (BM certainly comes to mind as mentioned) were overtuned and the nonsensical 270-degree cleaves and pack-a-mage requirements were less than optimal. Given that the expansion has a shelf life, I'm a lot less bothered by the difficulty level "changing" over time as gear improves than I am by anything that requires you to bring a "replenishment" buff going forward to survive a long mana test. Especially because the option to use potions won't even really be there.

On the subject of non-linearity, while I agree that it's not required per se, there was something to being able to farm select bosses in the old game that seems lost. Maybe I'm wisftul and the TBC were dungeons were relatively small and it doesn't really much matter. But even if you had willing friends in TBC and wanted nothing from, say, Shattered Halls except an item off the two-headed boss, there was absolutely no way to bypass content -- and reward -- to get there. Seems to me the 1-day heroic lockout was enough to prevent this mechanic from being overly abused and the loss of rep and other possible rewards on the way would've been sufficient to discourage this. But instead it's just not there. Even when you can see the next bosses (Magister's Terrace), you can't get to 'em in nearly every case.

ZA, when it was brand new, was an exception to this and allowed you to fumble around and learn the encounters at your own pace. In fact, it was probably one of the best and worst things about TBC. Fast reset instances are a win (gone in Wrath), unique 10-man content as a change of pace from raiding the same old 25s was nice (gone in Wrath), a challenge that initially seemed insurmountable (the Amani War Bear), but eventually become something routine you could look back on and remember having achieved.

I feel like beating the ZA timer, killing Vashj and killing Kael were about the closest things to "achievements" in TBC. And that's both a credit to the game -- it offered those opportunities -- and an insult. We did BT when you needed to get attuned. Our guild, fairly "serious casual" had really little trouble with it and eventually took a weekend to beat Illidan. I think it was exciting, but somehow less so than Vashj and Kael. To me, Kael was / is the greatest boss fight in WoW to date. I've not seen Muru and KJ so take that endorsement with the appropriate grain of salt.

By the logic that a loading screen is the same thing as logging into a server, it would make sense that continents and such are on the same server. Thus what the person you quoted mentioned in the AQ event causing lag in the whole of Kalimdor could be true, since they're on the same 'server' (or process or whatever). What this server is and how it works can't really be known until Blizzard discloses official information about it... which I doubt is going to happen.

Whatever the truth about that is, it's pretty irrelevant. Dalaran isn't much larger than Ironforge and everyone who's been to that city and witnessed a raid to Magni knows the true meaning of server lag. Whether this lag affects everyone on the continent doesn't matter much, since a zone that's unplayable is still unplayable.

One of the worst arguments I saw in BC was over Nethermancer Sepenthrea. Our tank needed the breastplate but the other three in the PuG didn't want to deal with her. Cue group implosion.

The issue of bypassing content is a sensitive one for many reasons, all of which have appeared in one form or another throughout this thread. The issues of common goals, overhead and engagement are at the forefront of this.

First and foremost is the issue of common goals. If we look at the loot table for Warbringer Om'rogg we find he has mail caster shoulders, a caster dagger, cloth caster boots, a bow and a two hand DPS mace. There is little/no incentive for any tank to care about this boss beyond ties to their guild/friends. It has already been suggested that instances in BC were too compartmentalized, I can't imagine that further segmentation would be helpful for the formation of groups.

There's also the issue of overhead. Even if getting together a group for one boss is feasible, the time spent attempting to do so can be prohibitive. Spending an hour in a major city putting together a group that will last the ten minutes it takes to bypass content to the desired boss isn't particularly rewarding.

Lastly, there's the issue of engagement. As one apologist for BRD stated very clearly for all its faults it was indeed epic. The scale of the instance contributed greatly to that. Raids like Gruul's Lair and Magtheridon's Lair get away with smaller scaled instances because the bosses themselves are gigantic in form and mechanics. Some of Warbringer Om'rogg's substance is lost when he is effectively removed from his environment.

I think the real problem here isn't that content couldn't be bypassed, but that it wasn't optional. For many classes there was one, maybe two items per slot for their role in the dungeons, some of them locked in heroics. If you needed gear for that slot you had to run one specific instance until you got it, rather than having options in the form of quests or alternative drops. Not all slots were that bad, but I'm sure a number of Warriors could tell you of their frustrations trying to get Shoulderguards of the Bold. If itemization were somewhat better the issue might be alleviated.

These are just observations from the beta, but I had my warrior camped in Silvermoon, and my Death knight leveling through Outland. Whenever Outland got a 'world server is down', my Northrend and Azeroth based characters would likely be available, unless multiple servers were down, but my warrior would be unavailable, and /who checks for the areas would yield no results.

The DK starting zone is initially an instance, and is on the same server as Northrend. There is also a non instanced version of it, on the Easter kingdoms server but it's only accessible after the entire Death Knight chain is completed. In that sense, it's expected that the whole Northrend server requires WotLK, and generally the people chosing to reroll to DK will experience the same server failures as people leveling in Northrend.

EDIT:
Zones and Quests
Hellfire felt epic, and more than that, it felt familiar. Overall, it was a great area to start the expansion.
Zangamarsh was pretty nice, but it suffered from an insanely implausible story line, even for a fantasy game. The design was great, but... come on... Nagas stealing water?
Terokkar was just... bland. And what the fuck is Auchinodoun doing there anyway? Because there's no quests to actually tell us what the story behind it is. Remember all the quests telling us what the Blackrock Mountain story?
Nagrand is great. It has its share of problems, though. Firstly, Halaa, and everything it implies. Then the Elemental plateau, concentrating much of the crafting productions' raw materials in one single place.
Blade's Edge. Awesome in design, but rather cumbersome to navigate.
Netherstorm and Shadowmoon were both very original, and they felt epic in their own individual ways. Both of them were very rich lore wise (especially Shadowmoon Valley - remember Cyruk? but the Kirin'Var village was also great) but they suffered from a lot of bugged quests at first.
The daily quests were a great addition to alleviate the grinding, but even more so, they reinvigorated fishing and cooking, and they added some incentive for the antiquated battlegrounds.
Overall, the massive problem that BC suffered from was that the lore was concentrated in Hellfire and Shadowmoon, mostly, and the Horde got a bit of a history lesson in Nagrand.

5-men content
While vanilla WOW offered us very little (Scholo, Strat and Dire Maul for end game, and BRD\LBRS for leveling and preparation for MC), BC hit us with a multitude of dungeons and their heroic versions. Diversity, no question about it, but it made looking for groups a lot more difficult. Also, the dungeons had some more inherent problems. Firstly, they were short and straightforward, which is great for PUGs but that's a horrendous loss in terms of feeling. The lore, as I said, is sublime, but it's completely missing for most dungeons.
And there's the heroics. Totally abysmal idea. The rep grinds for the heroic keys were a bad idea, but by no means the worse. Heroics were meant as something to prepare you for raids; something to do before you jumped into Karazhan. Except they needed full tier 4 groups for that, which kind of defied the point of going there. Oh, and there were 360 cleaves And you needed to run every guild member through some of the hardest if you wanted to raid beyond gruul.

Raids
Pretty piss poor tuning prior to 2.1. Some exceptionally well designed encounters (KT, Vashj, Hydross, bar the absurd resist check, ROS, Teron, Illidan, Kalegc, Magtheridon). The problem was that you couldn't bypass tier 5 content to Kael and Vashj while progressing in BT/MH, and the attunements were probably a good idea turned bad. BC is full of those. The systematic nerf system was probably a good idea, in terms of progression, even for perfectly tuned fights like SWP.

PvP
The battlegrounds turned stale in the absence of a ranking system. The daily quests sort of rejuvenated them, but there's still work to be done.
The arenas started as yet another great idea, but it turned tits up somewhere between S2 and 3, for various reasons *cough* class balance *cough*.

Professions
Jewelcrafting was a nice profession, but the fact that you could only pick it up after you had upgraded to burning Crusade created some massive economic problems. Apparently, Inscription is trying to avoid that, so Blizz learned the lesson.
Blacksmithing had a nifty idea to reward crafters, but sadly that was a massive fuck up, as warriors and shamans found themselves pigeonholed into Hammersmith, with little other benefits. Every PVPer had a stunherald. Every PVEer had a Drakefist.
Engineering still sucked, especially since you couldn't turn in shells for arrows, and there was little utility except for a tier 5.5 ish helm.
Everything else was rather fine, after the 2.1 Alchemy changes. Oh, yeah, the discovery system wasn't a good idea for must have items like flasks.


Misc


Best and Worst
Best: Kael'Thas 25 man, Hellfire Peninsula, bombing run quests,
Worst: rep grinds, the place of heroics in the progression chain, the distinct lack of lore surrounding dungeons, the arena balance

To put my stance on these things into context - I was in a mediocre raid guild in original WoW; completed Molten Core, Razorgore down in BWL, but that was about it. Crucially, that means that we hadn't really had the opportunity to see much of how Blizzard refined and improved their instance design; hence coming into TBC, while I agree that artistically the instances were fairly dull (with a few nice touches such as Magtheridon being audible and visible in Blood Furnace), in gameplay terms the content was actually a bit of a (positive) surprise for me and my friends. One I recall vividly was our first run through Shadow Labyrinth; three of the four bosses in there felt *new* and *exciting* to us, and the tactics that were required for it engaged me far more than Baron Rivendare or Darkmaster Gandling ever had. I also have to echo the various statements about the Caverns of Time instances; rethinking the concept of an instance in two very different ways made those instances really stand out as fresh experiences.

Karazhan worked very nicely as an introduction to raiding. A lot has already been said about the appropriateness of a 10-man entry to a 25-man raiding world, which was a very major flaw, but as an instance in itself it felt like it was paced very nicely and there were no fights anything like as bland as Golemagg or Sulfuron Harbinger; it was a much better introduction to the playstyle than MC ever was.

Breaking away from the original guild to try to make reasonable efforts into 25-mans did bring about a few further problems; recruiting shamans on alliance side was extremely difficult for quite some time for a guild which didn't already have a name for itself. We played through much of the T5 content with at most one shaman if we were lucky; I do sometimes wonder if we'd have had more success if we'd been able to pick-and-choose our raid groups a bit more. In terms of the instances there, Tempest Keep always struck me as designed in the wrong order, where the boss closest to the entrance was significantly harder than either of the bosses in the wings. Vashj and Kael were two excellent fights, particularly the latter; and one of the achievements I'll be proudest of from TBC was beating pre-3.0 Kael.

Zul'Aman always struck me as a little too hard for the gear you'd be doing it in if you'd just come out of Karazhan. Clearly, given there were success stories in that respect I was somewhat incorrect, though! The timed run was a nice idea, always felt achievable but required effort to get there; I'm looking forward to more things like that in Wrath (if not for real rewards then at least for achievements).

There's been quite a bit of talk about the pacing of the release of content, but for me being in a more slower-paced guild, it never really affected me negatively; however, the constant injection of 'new' content by gradually removing attunements kept our raiding interest alive, I feel, and helped us immensely in avoiding getting stagnant.

While I've spoken mainly about instances, there was one class balance issue that cropped up which bothered me a bit; our MT originally was a long-standing and experienced prot warrior, and I was dabbling at launch with the new and exciting prot paladin spec. Due to circumstances beyond his control we lost the warrior for a considerable length of time, which meant I was thrust into the position of being MT in many situations. I was adequate, certainly, but there were enough situations which I really wasn't suited to that I found a bit annoying; I sometimes felt that I was a hindrance to the guild (but contrarily, the best-geared tank, so still the best choice). I hope they do nail the equality issues for Wrath; I'm cautiously optimistic.

I have to agree with some people who have noted the problems with Sunwell drops. I would rather have seen them more like some SSC/TK patterns that drop *slightly* more frequently but can also drop from the bosses (i.e. Kalec).

Zones and questing were fun, save for BEM. It's a rather lovely zone in general, but it's a horror to level through. Terokkar felt weird because its quests were reallllly spread out. In Zangarmarsh/Hellfire, there were about 10 or so quests that you didn't pick up at a quest hub. In Terokkar, the large majority were not at hubs. I loved the art and looks of the zones, but questing in them was no fun.

I liked a lot of the 5mans the first time through. Heroic loot wasn't good enough quality, though - especially in the level 70 heroics (i.e. SV, Arc, Bot, Mech) where the only real difference is the epic at the end and badges along the way.

I'm not a fan of arenas, so I won't go there.

BT and Hyjal are pretty easy instances. I wish there would have been a way to make guilds do Vashj and Kael more, as they're AMAZING fights, two of my favorites in the whole game.

I hate what they've done to AV. A mindless zerg where you try to keep it as short as possible doesn't hold a candle to what it used to be. Sure, 48 hour matches were a pain to get mark from, but I've had a lot more fun in AV than I did in all of TBC. Achievements seem to help a bit though. People are more keen on defending or capping stuff.

Never had much of a hassle there, as I dinged 68 about the time I entered BEM. Given a flying form, it's a really nice zone. I do agree with the comments about navigating it on foot, as well as the lack of 'safety' on the roads.