I think having the screen on the controller is going to be a big hook. This feature will be great when applied to football, baseball, or even COD type games, it really opens a door for game developers to have some fun with.
That or it will just be a useless gimmck. lol
I like the Wii but my guys are 'too old' for the kiddie games, it's all 360 COD, modern warfare, and Halo in our house. They are 10 and 12.