well, the people say that Wii isn't next gen but "new gen", cause the console doesn't goes the same way like PS3 and Xbox360.
I even don't think that nintendo "steals" must of the customers like PS3 to xbox360. like a PS3 user would not buy a Xbox 360. but Wii is almost a "co-console". a console nice to have for something that is not like xbox360 and PS3.
Wii is on his own and got no enemy, at the moment.