Mario Kart 8, Wii Fit U and the next 3D Mario, all of which will be marketed to insanity, will ensure it'll take off like crazy later this year, setting it on the path to sustained great sales. I'm pretty sure of it.
Depends. If it looks like Mario Kart Wii, then it won't. In fact it'll make more people think that the Wii U is just a pad for wii games. We have all seemed to have forgotten that the Wii U launched with one of the biggest selling franchise games of the Wii, and yet sales have yet to take off. I don't see why other less popular franchises will work if NSMBU didn't.