In response to your questions:
Don't limit how many games per genre, just list good games, if there 5, so be it. 18? Thaat's ok too.
Year of release is actually helpfull to some.
MC and GR are ok, but I'd link to VGC reviews.
I think games should be placed by similarity within the genre, not by score ar filed aphabetically. For example Kororpina would go next to Marble Saga (which needs to be added :)) My Fitness coach or EA Active next to Wii-Fit. Make sense?
All in all, looks fantastic.
Wii Code 3456 7941 4060 2924