I can't see how the wii version looks any better
It doesn't. Matter of fact, its the EXACT Gamecube version with Wii controls tacked on - for some people, it makes all the difference. Which is why I'm not so overly hyped on it and I don't consider it a perfect representation of the Wii quality. I'm actually considering getting it for the Cube instead. Now as for Metroid Prime 3: Corruption, from what I understand was design for Wii straight up and actually makes use of the Wii's graphics capabilities (then again, i could be wrong on that too...)
Please don't tell the retro games thing is worth the money, I'm really not happy to pay to download twenty year old games when I already own them on the original consoles.
Its not. Its for folks who haven't discovered what emulation is.