It was very possible, dunno where you got that idea it wasn't possible from. Someone in this very thread mentioned his (or her) guild zerg'd it on 10 on first week. Took me 10s to find the vid: http://www.youtube.com/watch?v=3QUMvb2ZCPU . 10m guilds just never bothered with zerg'ing because it wasn't necessary.
I'd be interested to see a 25man version video of this
Seems very unlikely. My guild has some quite decent dps (top 10-20 on the majority of heroic bosses when you exclude bugged logs, Chinese and double logs on worldoflogs in terms of kill-speed), and we'd never even get close to that. ALOT more gear is neccessary. Main issue is the fact that 25 man already drops healers (going down to 3-4) to get where we are on the boss ATM - drop one or two more (depending on if you 3 or 4 healed), and you'd be unlikely to just survive the normal encounter damage. Which basicly means that what 25 man does is already a "zerg", per say - we can't optimise the setup to get more DPS than we do.
a blood dk can keep himself alive vs the boss easily past the first shield (did it on first week of hcs just to see if it was possible) but the burst required to kill the boss just before the first shield would require 9 enhancement shamans XD - maybe with nerfs this will be a viable tact but yeah XD
maybe with the nerf coming up a nerf strat should be really viable. we will have it a try. yesterday was our first attempt at all on this boss, and we just zerged him without anything to watch. we came to 55%. now we maybe can build a strat around that. what to kill and what to leave out.
The nerfs are said to be around 10% (a tweet said so at least). You won't be able to solo the belts, but one healing with a disc priest and doing maximum damage will definitely be a lot easier. Killing boss before the sixth belt that is. Mines are nerfed either way though, so it may be better to just do it the fatboss way.