http://www.youtube.com/watch?v=b_yhlHOzp78&feature=player_embedded - Hyperlinked because I don't know to work Youtube videos on this forum.
Obvious spoiler-warning, but this gives a good idea of how the gameplay in Goldeneye Wii's single-player campaign will work. It seems to taken quite a few pages out of Modern Warfare's book, with things like aiming down the sight, stealth sections, first-person cinematics, and a few quick-time events.
Honestly, I don't think it looks too bad. It's at least shaping up to be a competent FPS (although it doesn't show how smart or dumb the A.I. is). Personally, I'm hoping there's some gameplay elements not shown that help make it stand out more from other shooters. Going on a few undercover missions and experimenting with some spy toys would be great (exploding pen, anyone?). I'll reserve judgment for now, but it looks like the gameplay will at least be at the current benchmark.