2D? Don't be rediculous. 2D games look outdated... well, 'cause they are. Let me get something straightened up here. First of all, a sidescroller can still be in 3D. 3D models have more capabilites, and dimension, than sprites. Would you rather have a cardboard cutout of something you like, or an actual model of it? Simple, right? Again, sidescrollers are still very very possible in 3D, really, the character doesn't even have to move in the third dimension at all, and the graphics can still be 3D. Also, if it is the art style you like, that can be remade in 3D, too.

Oh, and don't let last years 3D games make up your mind on what 3D is like.