Hmmm, gee....lemme think:
It sits in the corner collecting dust in my households that owns one now.
It's successor was rush out INCREDIBLY fast mid-Gen to make up for all of it's myriad of shortcomings and mistakes (most notably because of the absolutely horrid 3rd party support).
Nintendo realized the Wii's success was fools gold and not a blueprint for long term domination. Gotta have HD, gotta have something NEXT GEN under the hood, and oh, GOTTA HAVE A CONTROLLER. The motion controls should ALWAYS be an option. Not mandatory to play EVERY SINGLE GAME.