I don't think there will be any more expansions to WoW, I think more they will focus on WoW 2, Diablo 3, or whatever. I think they will just continue launch major patches until Wotlk will die out.
in a sense that sound a bit contradicting to me.
What is the damn difference between making a WoW Expansion and making WoW 2? Theres really none, they won't make a WoW 2 for a VERY long time, because it would be too pointless, Remaking Everything of wow just to add another story to it... Think about it, its doing the exact same thing WoW 2=Expansion, Same thing only WoW 2 would require alot more work because of redesigning everything.
Anyway they need to focus on Diablo 3, Not another WoW, or warcraft, or even a starcraft, they only have 3 franchises, Diablo, warcraft, starcraft. Unless they create another franchise they need to focus on Diablo 3 now(Not a mmorpg..)