Ah, I play Generations on PC now where it's far more responsive than the console version (I also have a PS3 Limited Edition Set with the figure etc. which was the format I originally played the game on) it really improves the game!
Sonic Colours though really feels like a Nintendo attempt at a Sonic game anyway. I can't wait to see what they come up with together, they really were finally truly getting to grips with 3D Sonic. Sonic Colours had a lot more 2D stuff going on as a "Modern" Sonic than the Modern Sonic Generations levels.
You know, as great as the Sonic levels were in Sonic Adventure 2, I think the level design in Sonic Adventure 1 was by far the best. It felt more open and less like a narrow corridor. I'd love something that mixes the two for a modern sonic, though I do love the camera panning to the side for some proper classic platforming action too.