Depends on how many mario platformers come out on the wii u, if it gets bundled, and how much the wii u ends up selling lifetime.
If the perfect storm happens and the wii u sells under 40mil lifetime, they release a second new super mario bros, and a sudo 2d mario like mario 3dland releases, its very possible new super mario bros u doesn't pass 10mil.
On the other hand if Wii U ends up becoming the most popular console ever, the game gets heavily bundled, and no other mario platformer comes out, it might end up at 30mil+.
I'm going to guess around 15mil. I'm assuming no other "new" super mario bros comes out, but possibly something similar to mario 3dland will. I'm also assuming the wii u will be below all three current gen consoles in lifetime sales, but I expect all next gen consoles to be below any of the current gen consoles. I expect heavy bundling next year over the holidays, but very little after that, unless ofc this ends up being the only super popular game on the wii u. In which case it might get bundled for a few holidays and be able to reach 20mil.
