The newer Kinect 2.0 will be able to do almost perfect finger tracking. Infact sign language recognition apps have been written for even the older Kinect (XBox 360 version). Check out the SigmaNIL framework and FORTH libraries offered with OpenNI.
You wouldn't see this in an XBox game though - the XBox SDK doesn't support it.
I think that the SDK is way ahead of OpenNI. Soon the more enhanced features of the new Kinect will make their way into games too!
sorry, when writing about the kinect I assumed the new one. even though it's not available yet, it is more compareable to the leap than the old kinect, because of it's age :D