IMO next gen consoles are about introducing a technology that was notpreviously available, most choose to improve graphics, sound, game depth etc, making the same games more entertaining and iteresting.

Nintendo decided to go a different way and change how the games are played, designing a console which makes the user more phisicaly involved, and with the growing concern over obesity who can blame them. Nintendo had to do something different, releasing a system with similar gameplay and graphics to the 360 or ps3 wasnt going to win them any new customers or convince the users of those systems to buy the Nintendo instead.

I think graphics are an important part of mostnext gen systems but, obviously by the sales figures theyre not the be all and end all. I bet the next Wii will have much better graphics though.