Yeah...but that won't sell that many Revolutions. It needs to BE a Revolution game. It needs to take advantage of the new controller in profound ways -- fundamental ways. It needs to take advantage of the increased horsepower, with higher res textures and more onscreen stuff like particles and lighting, etc. Mostly the controller. They can't just add a fishing minigame that can use the new controller for Revolution owners, but otherwise will play fine in the Gamecube. They need to rework the control of the entire game from the ground up to use the Revolution controller. And it has to really shine.
I mean, I don't know that they will do this, but I think they should. It's not just a matter of being able to play it on the Revolution. It's a matter of WANTING to play it on the Revolution rather than the Gamecube.