The market for games using motion controllers is already 65M strong, so... I think publishers will tend to want to make Wii/PS3 casual games over Kinect casual games. The Wii/PS3 SD-HD difference won't matter so much for casual titles -- it really comes down to raw cross-platform marketshare.
That said, I don't think there will be much software support for Kinect, casual or otherwise.
Move for certain. The software library will matter.