I think folks are missing the point
The wii appeals to the other half of the market - women ... remember them? Bet most of the posters on this page are men.
Although there are notable exceptions, most women aren't terribly enthralled by the latest graphics hardware or ultraviolent FPS. For us men who are, the difference between PC / Xbox / PS3 may be of interest ... for the fair sex, there is really only one option.
Ditto for parties / older folks (many of whom seem to enjoy the Wii).
Nintendo has cornered the market for everyone but young male FPS players. Which is why I'd reckon a lot of the posters on this page aren't impressed by it - it's not aimed at you, lads. It's aimed at your other half.