You can't patent an idea : only specific implementations. The way to cover an idea is to patent every possible implementation of it. Another example implementation could be Sony using a wand prop with LEDs read by EyeToy, combined with inbuilt motion sensing.I thought that the general idea (of a wand which translates the movement into the screen and the direction your pointing at) can also be patended.
As for such inclusion on XB360 affecting Wii, I doubt it. MS certainly haven't pushed their camera to any degree so far, and even if the wand is well implemented, Wii has the mind-share. If you want waggle-games, Wii is where you'd go. MS would need to do something amazing to have shoppers decide to get the unknown MS solution over the known Wii solution.