I dissagree. The PS3 has a few advantages too.
The most important being that developers can make the games with the hard drive in mind (maybe for caching of textures, etc?), while the Xbox 360 can't, so will be more of a favourite for developers I think.
I think in terms of games, though, it'll be rather equal.
But, yeah, I believe the Wii controller will offer a new type of immersiveness not seen in a game as of now, and graphics won't matter either (even though, they are looking surprisingly good so far. More CGness than I've seen in PS3 or Xbox 360 as of now for some reason)
Imagine using the analog stick to move, and the movement controller for looking around, and sharp stabs with the movement controller would result in a punch in the direction your facing, or a reload of a gun.
Or a much better idea, on a first person shooter, when you take away your weapons, and you just have hands, the movement controller being the hands.
So to pull a lever, you'd move your arm forwards resulting in the games arm doing the same, and then push a button to grip, and then pull down with the controller to move it down.