Even though I dont like motion control games much I am not sure if this is a good move :|
I fear many possibilities will not see the light of day because the camera wont be fully potentialised whereas MS has the thing packed in with every console and making it a primary feature.
There will be a time when nice features will find their way on the XBone but the PS4 wont be able to compete because of a fragmented userbase. And that would be bad in the long term for Sony