Warcraft Four: Yes Or No?

Absolutely, yes. With as much work as they put into WoW as regards balance, backstory, and sheer quantity, a new Warcraft RTS utilizing all that would be great. I don't know if they should add a third faction to match Starcraft or not, though; the Horde/Alliance play with multiple races is each was fun enough.

WoW is basically Warcraft 4, they continue the story from there