Always thought it would be cool to make a story-based (sunshine doesn't count) platformer that takes him back to his roots. Actually start him off in Brooklyn (kinda like in the movie). Bring back the power ups including brand new ones. No backpacks, no timed items. Even allow him to have his trusty hammer. As for the style I really don't care for how Mario looked this gen except for the paper Mario one. I would kill for a cel shaded Mario platform where he looks like paper Mario...or at least until he gets a mushroom.