The game looks great. Maybe I'll pick up a Wii U when Smash comes out. That'd be kind of hilarious because the first two games I got when I bought the N64 were Super Smash Bros and Mario Kart 64.
Anyways, my only complaint I have from things I have seen is the roster of racers. I appreciate the amount of racers with 30 of them, but I wish there were more variety besides two metal clones, and 5 baby characters. I would have preferred Dry Bones, Wart, Professor E. Gadd, King Boo, or other unique characters from the franchise. Of course, that probably won't stop me from getting the game if/when I get a Wii U.