IGN's Look at the Controller's Possibilities
It's a comprehensive article. Read it.
The problem is that those possibilities don't make up for the basic functionality that it loses (especially if the motion sensitve stuff doesn't work 100% perfectly, rendering it useless for percise functions). It would be neat as a seperate, optional controller for some games, but as the main controller it has to work for a wider range of games, many of which won't be designed specifically around it.