The thing is, certain groups become famous for creativity, but I'd think just about anyone working in the game industry wants to be creative, and Wii offers the chance to let those creative juices flow. It's maybe even a better chance for no-name developers than big-name guys like Kojima. He can probably do just about any project he chooses. On the other hand, Joe Blow game designer at Ubisoft may have a much better chance of selling a unique idea to the bean counters if it's for a new system that requires unique ideas. Wii is resetting videogames, somewhat: big names will still sell, of course, but brand-new names may have a better chance on Wii than they do on a more traditional system. So this is a developer's big chance to do something new, instead of working on the tenth iteration of some long-running series.
I'm going to throw this out there, without thinking too much about it, but I'll bet you'll find a lot more new franchises came out of Playstation and Nintendo 64 than the current generation of home consoles, and I think that's partially because they had this same, "we need new games to sell a new type of gaming" feel to them.