If the Wii wins designers wont be able to make truly spectular visually stunning games using techniques and technologies that the heavenly sword devs are. Things like what they are doing will make it so that you cant truly be taken in by the characters and make you feel right in the action.
I know im going to be flamed in every way for this but seriously think about it, does any Wii games other then maybe Zelda or Metroid really bring you into the action, or make you envision yourself as the character? I know the SNES and N64 did but I've played a lot of GC games, none really pulled me in (starfox kinda did).
You know why this argument will always be idiotic? Because it assumes that nothing spectacular was made before the PS3 and 360 and that every game before then looked like complete ass.
Also, you don't need to have machines capable of the most awesome graphics ever as long as you've got style. No More Heroes, God of War, Okami, Odin Sphere, RE4, Windwaker, Katamari Damacy, Rayman Raving Rabbids, and many many more will always look better than things like Call of Duty, Madden, Oblivion and all those other hyper realistic games will always be inferior to those previous games because they just don't have style.
As for Heavenly Sword, that game couldn't be more generic and cliche. I've watched all the videos for it and it does look interesting, pretty, and fun but it has no real style and everything just screams I'm a copy of something else or Hi! I'm not creative in any way at all. Some of the things they are doing with facial expressions is cool but lets look at Windwaker again. Link in that game has some of the most amazing facial expressions ever and that was don't on the Gamecube.