Yes it's a great party and entertainment machine but it just isn't a serious gaming machine
And that's exactly why it's such a great system for the living room / den. "Serious gaming machines" stress the single-user play. The Nintendo's strength is social activities. Sure, the graphics are not powerful, but how much graphics do you need to have fun?
Also, I've found the Opera browser on it to be quite handy for looking things up. Bookmark IMDB, Wikipedia, MovieFone, Local Weather, etc... Instant on/Instant off reference source.
And as for open development... There is a new unofficial homebrew channel you can run on the Wii. Also, you have the Opera/Flash platform.