I think SCII should be in 2D, just like the original StarCrafts. The reason I think this is because going 3D just effectively limits the number of people who can play the game (and play it at a somewhat decent framerate). Keeping the game 2D allows much more expandability with the game itself, allows it to run on everyone's computers (I still play StarCraft on my 266mhz computers and it runs really smooth). I think 3D is a nice touch to RTS's, but when it's done just for the sake of having the game in 3D, it's annoying as hell. Take Generals for example. Easily the worst C&C game I've ever played. I think mainly because they spent more time making a (crappy) 3D engine for the game that needs a powerhouse computer to run decently.
Meh, you know what would be cool? If someone made a 2D RPG for the new next gen systems. Imagine that, you'd have an RPG that you could have hundreds, and hundreds of hours of gameplay, easily. People use too much space these days with 3D and modeling.
