Considering the time it took to make SC2, which in my opinion was more of an "ok" title than a real blast like SC, I can't help it but worry about the quality that will come out of such a "short" developpement period. I'll probably buy the others SC2, at least for the story, while praying it isn't another "space white cow-boy saves his girlfriend".
Seriously, anyone remembers the time when Raynor was just "a nice guy trying to do good", and when the player was actually spoken to by the characters, which felt WAY more immersive than having to play whoever the game wants you to.
Also, I think our only hope of ever seeing a Warcraft 4 would be for Blizz to declare the whole WoW continuity non-canon, which I think would be HILARIOUS.
Diablo 3, well, to put it properly, I played D2 : LoD, I liked it, but wasn't a huge fan (more of a casual player). So, to put it in a nutshell, I'm not going to get an always-online game if there is an equal alternative which I find more intriguing (because yeah, I'm more curious about the world of Torchlight, of which I know almost nothing, than about a world in wich you must kill Satan for the third time).