Personally, I don't really understand NSMBU as a launch game. It doesn't show off the second screens capabilities or the console's technical prowess. Seems like a poor choice to justify a new system.
Actually, the game does take advantage of the second screen (and also the social aspects of the Wii U's online). There's a multiplayer mode where a player with a gamepad can make platforms on the pad's screen.
But yeah, I don't mind NSMB U being a launch title (NSMB is a system seller anyways) but what was truly baffling was that there is NO 3D Mario shown at the conference in any way.
EDIT: Thought that mode was called Boost mode but now that I think about it... that doesn't make a lick of sense. :/ Was it really called Boost Mode or was that for something else?