I think the reason Wii is selling well, is people are searching for something different.
Gamers have been playing the same games in the same methods for years, and I don't think they want traditional games to disappear, but they do want to try something different. The Wii opens up new realms of possibilities for gaming.
Everyone else is just amazed by this bizzarre new product. It has been everyone, and people are being told it is THE next big thing. And look at it. Wii Sports has seriously captivated the entire media. Wii Sports and Excite Truck may not be the most polished games, but they are perfect Wii games, that literally challenge everyones concept of gaming.
The question is how long will this honeymoon with the media last? And does that matter? After the holiday season, Nintendo will be releasing games to hype up gamers, and to give those non gamers something to excite their purchase as well.
Nintendo just needs to keep big audience attracting games coming out for the entire first year to be a success...and it looks like Nintendo will be doing just that.
Mario, Metroid, Smash Brothers, Brain Training, Wario Ware, Fire Emblem, Mario Party, Pokemon
All these games have the ability to draw new audiences to the Wii, and different audiences as well.
Holiday season 2007, I think it would be important for Nintendo to release another Wii Sports game or sequel.
Be it Wii Motor Sports, or a direct Wii Sports Sequel with fleshed out game modes for Tennis, Bowling, Baseball, Golf, Boxing...and add new Sports experiences to the package as well.
Finally, a Wii update enhancing the Mii experience would be a huge boon for sales as well, specially if it came around the time that a few new games are released that use the Miis within the game.