Worried about the fast release schedule

If they release all of vanilla over one year then head into TBC, is that realistically enough time for guilds to gear up their 40 man raids?

If you’re unlucky with drops =\

I’d imagine Blizzard will allow the option to remain Classic and provide a transfer to an Era realm for those that do not wish to continue beyond the Dark Portal.
However I think this is also a Golden Opportunity for the possibility of a The Burning Crusade Era realms?