I remember how difficult it was on a 30k server and I don't anticipate many full servers still cruising along six months after launch. My fear is that there will be zero room for 'casual' raiding guilds (those that spend a half year in MC/ZG and then creep their way through BWL for another six months--if they even finish).
I had a solid 50 raiders in my guild, enough to switch players out as they needed to afk and a few who didn't mind questing and such for the 3-4 hours to get their DKP if they couldn't land a spot. That said, when even one or two people left or quit the game, it was noticeable. The spreadsheets, the necessary class distribution, the required 12-16 hour/week commitment JUST for raiding. Are people really wanting to do that again or is the consensus mostly just wanting to experience some nostalgia and then go back to retail after a month or two?
I guess what I'm saying is that I really WANT to raid Vanilla again (I actually miss MC), I loved my lock, I was solid dps and definitely put in the time. I just feel like this time around it's going to be either tank, heal or be prepared to solo for a looong time in one of the very few sustainable raiding guilds that can keep their shiz together.