Now the picture is clearer and it has indeed been shown to not be able to offer a significant experience to gaming.
I completely disagree. Absence of proof is not proof of absence.
There are things I am certain that would work that have never been tried. All you can say is that Kinect has not offered a significant benefit to gaming, but you are not able to say that it is unable to do so.
Trying to map controller functions to body motions is a fundamental limitation in thinking, not in the technology.