Again the statement wasn't that the Wii isn't more powerfull than the Gamecube, it is that the Wii is a refurbished Gamecube hardware wise. And since most of it's architecture is indeed identical this still holds true. It's also stated that Nintendo will probably be the first to come out with a new console because of the Wii being least powerfull console of this gen, and that's only logical aswell.
I really don't see anything wrong in what this Ubisoft dev said.







