I've always been divided on motion controls.
On the one hand, some of the stuff the Wii put out is hella fun to just fuck around with when you need to blow off some steam. Call me nuts but when I need to work off some excess frustration I find that humiliating the loser AI in Wii Tennis serves me just as well, if not better, than even the most overblown killing spree on Saint's Row 2. Cause it had that extra level of involvement. Instead of just pressing buttons and watching things die, I can physically work off all the stress that's built up in me for whatever reason.
But on the other hand, you have the argument that motion controls, when shoehorned into 'hardcore games' (a term I hate with the white-hot intensity of a thousand supernovas) can break immersion. And I find this is true as well. When I'm playing, for example, Half-Life 2, or L.A Noire, or Prototype, or any of those other big, Triple A core titles, the necessity of having to waggle my arms around to make shit go down is an unappealing prospect.
Reaching some balance between these two is what's needed to really make motion controls take off. Nobody's going to accept motion control if it's only reserved for casual titles but they're going to outright reject it if it's carelessly forced into big-name releases.
We need a compromise. It's what I think Kinect is working towards, and it's what to some extent the Wii-U is going to help achieve (only not with specifically motion controls, but just putting in more than just standard control layouts and leaving it there) so I think that in the upcoming years and into the next proper console generation we'll hopefully see less people bitching about motion controls as they become used in more sensible ways to benefit 'hardcore gaming' as opposed to working against it.