The way I look at NSMBW is it'll either go the way of Mario Kart or Animal Crossing:CF
Neither of those games were revolutionary or even did much to push their franchises forward.
However Mario Kart allowed you to drive with a wheel - included! - and was fun for all ages. Someone anyone and everyone could grasp. It also added online to classic game play. Sellable to core and expanded audience.
Animal Crossing did too little to innovate. It really didn't make use of any Wii functionality at all (except Wii Speak) and didn't effectively convey what it was to the uninitiated masses. It was also WAY to similar to AC DS and AC GC to sell to the core. A tragic missed oppurtunity.
NSMBW is immediately relatable to anyone who has ever played or even seen a video game. People immediately 'get' it no matter who they are. Looks like fun. Multiple people can play together (like MKW, unlike AC:CF). It innovates enough the core will definite buy it. Easy and fun for the mass market.
Yeah, it's easily got a shot at 11m in one year. It'll all depend on how fun it is to actually play.