Let's hope developers make good use of the controller. From what has been seen so far, the motion sensor translates your movements into simple game orders. For example: If you swing the controller upwards, the game interprets the "up" order and your character model performs the "up" animation. If you moved the controller in a slight different angle, the difference won't show onscreen unless there's an animation for it.
I'm sure Nintendo will polish it for their games, but I'm not sure third party companies will do the same effort.
Our hopes were a bit high when we thought about accurate swordfights...