I don't even consider these bosses, more like trash with a guaranteed junk epic.

Take MC as the extreme opposite. If any boss there had been optional, you could tell by the number of times it was killed on spoiler sites alone because for months guilds that had Nef down only went there for one reason: Ragnaros loot. If exalted Hydraxian Waterlords would have allowed players to summon him, the only other boss that would have died is probably Gehennas for two Nexus crystals.
However, a guild still on Vael would still clear the entire zone to gear up. No one would really consider these bosses optional for their goal.

I'd argue that the first "soft berserk" you encounter is from Ragnaros. Nothing is preventing you from killing him in three or four or five spawns of the Sons of Flame ... except that you almost certainly won't survive the third one (and many newer groups won't survive the second). To be honest, I *hate* hard berserks - I realize that they are put in place in some encounters to ensure that the fight is done the way it's supposed to be done (i.e. the ranged berserk on Patchwerk to prevent kiting). It's always felt gimmicky to me, though that Hakkar decides that after 10 minutes he's had enough, rather than just wiping the raid to begin with. *shrugs* It comes down to gameplay vs. realism at some point, though, and I'm obviously not complaining that gameplay wins.

The basic point, though, is that effective time-limits have been around for a while.

Pfff, it could be "fight me without your toys" - stops you burning trinkets or long cooldowns. Just a straight check on what your baseline DPS is. If he doesn't target you? Bully for you, you managed not to get tested this time round. Better make sure you're up to scratch in case you're the one being tested next time though.

The point is to invent a mechanism to intelligently test the output of DPS classes on an individual basis, rather than the main test coming in the form of an enrage timer - "your raidwide DPS wasn't enough to kill me in 10 minutes, so RAARGH I KEEL YOU!"

The enrage could be masked in various ways.

Magtheridon: Like somebody allready mentioned, the cubes could break/run out of power
Hydross: He could do an emote where his body becomes unstable by all the phase shifting and he starts to spawn both nature and frost adds +marks(now that is a bezerk timer tbh, would be an awsome sight)
Void reaver: When you engage him he starts to charge a nuke and the fight is no longer killing him but preventing him from blowing up the whole room after 10minutes (at 10minutes the nuke is charged and he uses it, doing ticks of 10.000 damage every 5 seconds)
Netherspite: He calls for more nether portals, and it gets harder and harder to keep up(from 3 to 10 portals in 1 minute)

I am not stating they are good sollutions but at least they take away the "lol 10minutes PEWPEW" we see now.

Yeah, that's what they did with vashj and it's much more fun even if it's still a good old timer.

Give the poor blob some credit, he drops Scarab Brooch.

What I as healer hate about enrage timers is that even if I do my very best as a healer with 'super mega imba optimal healing' it's still a wipe since at the end it's not a matter of my mana but rather the time it takes to cast my heals. This is ofcource a counter to bring alot of healers fights. But it's still sad when it's not your play nor your gear, but the time it takes to cast heals that matters.

Enrage timers are a good concept by Blizzard because they force you to adhere to a semi-standard group comp. If we didn't have them, think how many raids would just run healer-heavy groups and slowly wand the content to death!

But I agree with some of the above posters that enrages nowadays are too bland. Not having enough DPS at the 10 minute mark shouldn't be a guarenteed wipe. That kind of stigma will often demoralize a raid when you're "behind" on DPS. I can tell you first hand that it's frustrating as hell to hear "pick it up guys, we're 2% behind" when no one has died and everyone has decently high mana-pools.

In TBC? Not very many.

All the healers in the world can't prevent hard-hitting bosses from eventually lucking out and getting a couple of stupidly hard hits back-to-back. It comes down to what was said above -- it's not about how long you can heal, but your HPS. Sometimes, HPS isn't enough to balance the hits.

A good example of this, just off the top of my head, is Maulgar. Once in a while he lands his Arcing Smash at the same time as his Whirlwind, and hits a regular melee crit too ... all in under a second. 15-18k dmg, in a second, completely unpredictable (aside from knowing that the specials are incoming). The solution is just to stack enough stamina to take those hits.

But as you progress, the hits get harder and harder. Once in a while, you're going to get a 25% resist on Hydross at 4 stacks (or 5, if you're holding him in nature a little longer), and your tank is going to spike *hard*.

The only way to beat the odds on random crap like this is to run with a balanced raid. The people who would cheese stuff by bringing 10 healers are just putting themselves in misery by forcing the fight to go longer and longer, and giving themselves more and more chances for that 1% OH CRAP moment to happen.

Running Hydross back across the line at 50% doesn't make the fight easier on the healers ... or anyone. Assuming he had no static enrage timer, so you basically could fight him as long as you wanted.

Tank healing on Hydross isn't particularly hard, unless you're running well past 250%. At 100%, we rarely see spikes, and when we do, they're not for enough to worry about with 3-4 healers covering it.

But if you swapped him back at 50%, ya, you'd never have a high level Ice Tomb ... but you'd also have under 15 seconds of dps per phase. Even assuming 15 dps who can burst 900 dps each for 15 seconds, that's 14 transitions to get him down, assuming you got him down 55 seconds at that same high-level dps in the first minute.

14 transitions, each of which is lasting just under a minute.

And every single time you switch, you have to worry about dps pulling him back across the line, or tanks not picking up the adds quite quickly enough and losing a healer, or the 2nd MT screwing up his threat moves ... over and over.

You're welcome to try that fight. I'd much MUCH rather deal with the higher level tank healing (and DoTs / Ice Tombs) than leave 14 full transitions (probably more, because few raids can actually put out 13-14k dps consistently over a long time period) to chance.

My argument is basically ... the shorter the fight, and the fewer repetitions you force your raid to go through, the less chance you have of screwing up and wiping.

Think of C'Thun. Why would you care about getting him into Phase 2 fast? Phase 1 is nice and simple, right? DPS the big thing in the middle, eat some green beams, and dodge a big slow red thing moving around the room.

Wrong. Every single time you had a Dark Glare was a chance for someone to screw it up. And every single green beam was a chance for some retard to chain 3 or 4 other people and wipe the raid. So you pushed dps as hard as you could in Phase 1, so you could get to the relative breathing-room Phase 2.