So I tried my first Heroic MT run yesterday with a guild group- generally all in T5 equivalent gear. Our group was:

Feral Druid
Fury Warrior
Fire Mage
Beast Hunter
Holy Priest

Which seems like a pretty well rounded group to me. We blazed through the instance (we wiped once on Vexallus because of bad add management), and then we hit a complete brick wall when we got to Priestess Delrissa.

We had:

Priestess
Demon Hunter + Pet
Arms Warrior
Fury Warrior
Warlock + Imp

After 2 wipes realizing that the warrior's fear was not going to be enough of a CC, we swapped him out for a warlock. With this make up we were able to get very close by banishing the hunter, sheeping the warlock, hibernating the hunter pet and trapping one of the warriors (apparently Seduce does not work on any of these adds, which we found out the hard way). We had no problems downing the Imp and the Priestess quickly, but unreliability of the hunter trap meant that there were two warriors running around interrupting me (the healer) and we wiped about 4 times in a row with not being able to get farther than 3 kills. We had to eventually call it as we had to go to SSC anyway, but (not to sound arrogant) it really baffled me how horribly we did on this fight.

The main problem I had is that I feel like if I went in there every time with a similarly geared Pally Tank, 3 Mages, and me, we'd never have any problems (as the Pally Fear, Sheeps, and Frost Novas are plenty of CC). With the fight set up as it is now I just can't imagine how, at my gear level, I could ever even consider bringing a non-CC class such as:
1) A warrior of any kind
2) A dps shaman

Until I'm more comfortable with the fight I'm probably going to even shy away from Rogues, non-surival hunters, and druids.

I'm going to try the instance again tonight with the "ideal" group that i laid out above, but does anyone have any tips for allowing me some more flexibility in my group building? Am I just a noob and missing some easy fix here?

I think you just forget what the difficulty of the previous heroics was before you had T5 gear, and before they nerfed the instances themselves. Trying to get a spot dps'ing without some form of reliable CC was next to impossible in the beginning heroics. While this is still just another 5 man, the mobs in it, even on normal, can put out a surprising amount of damage.

It's an arena match in the middle of an instance versus a team with a lot of hp but poor coordination/tactics.

Good tactics for Delrissa:
-Bursting someone down on the pull if you can
-Burning/stinging/draining the healers' mana (Delrissa does nothing after she's oom).
-CC/kiting/silencing

It's important to know that aggro doesn't seem to work traditionally... Have your tank swap to dps gear and get to hamstringing/dpsing/stunning or, as a Paladin, helping out the healer

I'm an Ele Shaman, and while CC classes are useful I felt I was useful as well. Tremor totem, grounding totem, purge, bloodlust, frost shock and Earth shock are very good assets--not to mention decent burst.

Uh, yesterday we did it with a less than ideal group with no problems (only wiped once on Princess because of feared into a pack we didn't clear). Our comp was: Enh shaman (myself), warlock, rogue, feral druid, and alt resto shaman. Granted, the rogue and warlock are basically geared out in full t6 and I'm almost up there, but our CC was very low. For Princess, we: sapped a warrior, feared the rogue, blinded the warlock, and torched Princess. After that, we worked the adds down one by one. Granted, bringing 3 mages like you said would easymode the instance, but it would trivialize every other instance as well, this is no different. Probably at t5-level, you can't burn down the princess as quickly, but if you coordinate interrupts, I can't imagine how you couldn't kill her in 10-15 seconds at most. She's extremely soft and only needs one interrupt and a dispeller to keep her from healing too much.

I would have everyone wearing HP gear as they should all expect to be attacked since as the previous poster pointed out, aggro isn't very traditional here and keeping aggro on the boss is less of a priority. Churn and burn works better.

The real pain in the ass in that encounter is the naga warrior. I've only got around 5k-ish armor in my leather/mail gear and his MS was hitting for 3.5-3.8k, and he was getting crits here and there over 4k. If you take a group that cannot CC him the difficulty ramps up tremendously.

My first run of the heroic mode we did Enhance Shaman, Feral Druid, Hunter, Prot Warrior and a Holy Paladin. Basically little to no CC, all of us T6 geared, and we got creamed over and over.

Holy Paladin
Holy Priest
Rogue
Ice Mage
BM Hunter

All but the hunter t5, the hunter in blues/kara.

Poly=Shaman, sap warrior, trap what ever would get in the trap.

All cool downs burst the priestess, get rid of the hunter, and the take out the anything harrassing the healers.

I think that a warlock has the potential to be the best CC in this fight, but all the locks I have been with have been very poor, in fact a detriment.

Mages, spellsteel the priestess' renew.

I'm also a holy priest as well and my approach to this encounter was to basically treat it like the last 2 bosses in heroic Shattered Halls and wear some hp gear. [Spyglass of the Hidden Fleet], [Commendation of Kael'thas] in trinket slots (ironically the latter drops off this boss) and some gladiator pieces were fine, being in the region of 10k health meant I could take 2 hits from the warrior guys without dying. Can't hurt to use the 20 stamina food since it's so cheap. If you have a composition that keeps cc'ing you then you can also wear the PVP trinket.

Try and keep yourself shielded and PoM'd as much as possible since as Zifna mentioned the mobs don't maintain a normal threat list and you will "tank" them quite often. Health potions, instant heals and Binding Heal are all really nice here as well as Fade and even Psychic Scream if you pull them back. Wear the S3 gloves for the equip bonus.

We found it useful to cc whatever we could although did try it with only a warlock for cc last night, and always nuked the Priestess first. Dispel her Renews and interrupt her heals, she has very little hp and makes it somewhat easier to kill the rest of the adds when she is gone.

The Princess fight is definately one of my favorite encounters in the game just because it treats it like a PVP fight in terms of the mobs abilities and random aggro.

We went with...
- Prot Paladin
- Warlock
- resto druid
- mage
- combat mace rogue (me)

I sap the shadow priest, warlock banishes the demon hunter, mage takes care of sheeping the rogue. Our prot pally will jump on the warrior while I basically solo the Priestess. In this fight im running wound/mind numbing and the priest drops very easily after I start popping cooldowns. Basically the more cc you have the more trivial it becomes.

Yeah I had my pvp gear on, and I have almost 11k hp in pvp gear, and I also have the extended fear from the season 1 gloves.

I am very jealous that you have the spyglass, as all of ours have so far gone to tanks. I am wearing the [Alembic of Infernal Power] and my pvp trinket, but I am a little concerned that in my pvp gear i'm at almost 400 resilience, which is totally overkill for a pve encounter. I really just put it on for the stam, but maybe i'll swap the alembic back out for a stam trinket next time.

I didn't fade actually, cause I thought they didn't have threat at all, but I did use psychic scream and my tailoring nets to limited success.

Hm, I can't say for certain that it does. I got the impression that the mob moved away from me but it could have been that it was going to change targets anyway, or someone used an ability to grab it when they saw it was attacking me.

Speaking of the Heroic, how are people killing the 2nd boss and dealing with his adds on heroic mode?

We had a lot of trouble with the small orbs he puts out, not knowing whether to kill them in groups or even who to kill them with, ranged or melee. Granted, I could cloak a lot of the dmg, but that's only 5secs which even with a t6 group, is not a lot of time.

Ideally, you'd have a mage take two waves and then ice block out of the debuff, then have another class take two waves and cancel the debuff (mage or rogue), and then just go into full burn mode when he hits 20%.

We did it with a mage eating two waves and then a hunter tossing his pet on the adds, which worked out pretty well. I would think a warlock pet would be great at it too. With only like 1k health, even a VW could kill em.

All of the damage is arcane too (even the lightning bolt, which wowhead reports incorrectly as nature), so stacking arcane resist makes the fight a complete joke. The first boss uses tons of arcane damage too, so I think anyone heading in here should at least bring their [Violet Badge] to make things easier on themselves.

Our first group (entry-level T6 gear) was:

Prot Paladin
Arcane Mage
BM Hunter
Shadow Priest
Resto Shaman (myself)

We ran into:

Priest
Rogue
Shaman
MS Warrior
Hunter

First pull was brutal; the tank got kidney shot on the pull, I got gouged and focused down in a matter of seconds. We ended up sheeping the shaman, fearing/trapping the MS warrior, and burning down the Priest while interrupting/viper stinging.

Having the tank in DPS or Healing gear definitely helps as mentioned earlier in the thread. That rogue is certainly annoying though.

As for the 2nd boss, we have the mage kill the first 3 or 4 adds, ice block to remove the debuff, then split out the remainder of the odds between the group (A single earth shock was enough to take them down for me).

Kill the Pure Energy with someone who can clear the debuff off themselves when it hits about 3 stacks. I think it's about 300 damage per second per stack (but also a 50% damage output increase). We had a rogue and a mage with one of them assigned to each side of him, at 3 stacks the rogue cloaked and the mage ice blocked and then they were free to kill the last 2 and have 2 stacks of the damage output buff for the last 20%. Save all your DPS cooldowns for that last 20% when he starts casting overload.

Also, 150-200 arcane resist on the MT makes healing the tank much-much more manageable. His melee's are arcane damage (that can't be blocked) similar to Hydross' melee damage.

(EDIT: Yeah, pretty much what Bendyr said. Remember that on heroic he spawns 2 Pure Energies at a time instead of 1.)

(EDIT2: Also, I believe the Chain Lightning is Nature damage. At least that's what the combat log said, the rest is Arcane though.)

it's possible... my combat log is 10 kinds of screwed up ever since 2.4, but mine was definitely saying arcane.

These responses hit me from left field...
Heroic [ironically] felt easier than normal for us. If it was because we were new to the zone during our 'attunement' run, and knew the pulls afterwards... we'll never know. Avoid a melee heavy makeup for the 2nd boss as well as Kael (ranged kiting makes it ezmode).

Ran it with:
Prot Warr MT
Fury Warr
Enh Sham
Dest Lock
Holy Pal
and basically zerged the entire zone. Some pulls we used seduce, but honestly it wasn't doing much as it broke either because of internal mechanics, or WW/Cleave/totems. Wiped twice total.

Went back the next day with:
Prot MT
Fury Warr
Enh Sham
Mutil Rogue
CoH Pri
was a bit more difficult. 2nd boss especially but still doable, just not zergable.

We could go into the mechanics of each boss, but I'd rather not add to any spoilers. One fun thing is we putzed around with dps the second time, and saw Kael actually do his 25man danger move.. and hit the MT for 38k. Took us by surprise that that mechanic was included in a 5man.

Your understanding is wrong in that case. There are certainly cases of elementals that can be blocked, but typically these elementals will be dealing physical damage.

Hydross the Unstable, Hydross's various adds, and the Flames of Azzinoth all only have their damage reduced by resistance, and for all of them their attacks can not be blocked.

From what I can remember (It's been a while since I did Arcatraz or Mana Tombs), both Zereketh the Unbound and Pandemonius can not have their attacks blocked either, and also don't have them reduced by armor.

I've never seen a block tanking Hydross. I *thought* you could dodge/parry him but if you can, WWS isn't picking that up:

Taritus - WWS

Click to expand the "Damage In, Nature" line and it shows 100% hits landed on me but 60+% mitigation from my 360 NR. I also checked a post-2.4 log from last night that showed the same mitigation info for Hydross.

AFAIK, armor also doesn't factor into the magical melee mitigation (that's fun to say).

(EDIT: LOL, pretty much what Chicken said. I'm slow on the draw today I guess...)

If you kill the orbs you get a stacking debuff which increases your damage by 50 % per stack and does damage every three seconds. The easiest way to do this is having your rogue kill all the adds, singing in joy because he does now triple damage and clos'ing the debuff off after 4 or 6 stacks. If you don't have a rogue, it's probably the best to let the tank kill them all, so only one person ever takes damage and you can focus your healing on one person.

To sum up:

Warlock, Mage, and Rogue can each generally take two of the adds out of the fight for a significant amount of time. It is not at all unreasonable to expect a group to have at least one of those.

If you lack these, you'll probably want a druid and priest healer. They bring added CC in the form of hibernate/cyclone and aoe fear, respectively.

PvP gear helps. Playing like a PvPer helps even more. This means four things:

1) if you are being attacked, use your defensive abilities. For example, a shaman saying he had leather-like avoidance begs the question of why he didn't put on a shield.
2) Don't be afraid to use your pvp utility, such as mana drains and kiting spells/abilities, and focus on snaring/stunning/interrupting/debuffing/healing if you are a tank; put up trash buffs to prevent purge of vital abilities.
3) Plan for chaos -- a frost trap is potentially better than a freeze trap; AoE fears are extremely helpful, hp to take random hits is close to essential; pre-heal/buff/protect the weakest player(s) in your group, not the tank.

But, yes, generally speaking humanoid CC trivializes the entire instance. I did it with a warrior tank with buffed stats of: 10350 hp, 25.6% total avoidance, and 55% mitigation versus lvl 70s. How? Two mages, a warlock, and a resto druid (me) meant we never had more than one mob at a time up, even on Darlessa and the trash 5 packs. Further, much of the damage on the first, second and final boss is all elemental damage. And Gravity lapse Kael renders the tank little more than a healing sponge.

My real question is whether this instance is optimally tanked by a warlock. We have two bosses that do almost exclusively elemental damage, and of the two that don't, one doesn't hit extremely hard, and the other ignores traditional agro mechanics entirely. Of the trash, anything that isn't magic damage is fully kite-able.

Last, has anyone considered using an AR soak on Vexallus if they are having trouble? Reducing that 300 dps debuff to 75 would make the fight a lot less painful.

Back to the 3rd boss:

As others said, you have to play it like an arena team. If they're a 4-DPS-1-healer team, and you can't CC any of them, you probably want to control/interrupt the healer as much as you can and burn down the DPS that's most dangerous. Simply: If you're taking too much damage, first priority should be reducing the incoming damage. There's lots of places to break LOS on ranged-- a druid with cyclone/bash/maim/charge can keep Delrissa's heals from landing until the dedicated DPS can kill one of their DPS. A druid doing that, of any spec, might be better off in healer gear (if it's any good) for the purposes of this fight.

More particular:

Does resilience actually do anything, or is the PVP gear recommendation because of its stamina? Do the casters crit? Do the melee crit more than 5%?

The person who said treat it like an arena match was correct. Just kite/snare as much as possible, cc when/if you can and run the priestess out of mana as soon as possible. Once you get one of them down the fight starts to get insanely easy. Wear stam/PvP gear and you'll easily beat the encounter with very little CC.