Zelda Twilight Princess is the exact same game on Wii as it is on GC. Same models, same textures, same effects. The only thing that's different is that the Wii version can be rendered in widescreen. I don't know whether or not the GameCube is unable to that, but there's that.

I think that is the only differnce, the video I posted shows the Wii version in widescreen, the thats the reason why it looks a tad better in some cases, not anything big though.

Of course. You listed a majority of them.

As bad games as they were: The Conduit 1&2 look amazing. I don't think you could replicate those graphics on 6th gen consoles.

^ Also, the Wii version is a mirror of the Gamecube version because of Link's left-handedness.

the last story
Mp corruption
conduit
xenoblade
dead space ex
mario galaxy
resident chronicles
and many more

You have to remember that the hardware was basically the same as the Gamecube, just with a speed boost. So that means they hade a LOT of time to get used to the hardware.

That said the Xbox's gpu is on par with the Wii's, slightly more powerfull if you take memory bandwidth in to account. Altough Wii has slightly more RAM. So yes they could be possible on a 6th gen console if the developer hade enough time for it.

To be honest I didn't see much on my Wii that couldn't have been done last gen. You could argue that Mario Galaxy or Conduit were technically impressive but so were a number of Gamecube and Xbox games (e.g. Rogue Squadron, Halo 2, Splinter Cell: Chaos Theory, Riddick).

Super Mario Galaxy, Metroid Prime 3, Skyward Sword, Xenoblade Chronicles, Monster Hunter Tri showed that Wii could put out great graphics and games like Mario Kart/Smash Bros were a big step up from their Gamecube counterparts. Its too bad more developers didnt try harnessing its true power.

I don't know if it couldn't be done in the 6th Gen, but 'The Last Story' was as much a Wii tech demo as it was a game.