FallingWater -- that's the one that is falling apart because he didn't bother to do the engineering, right?

I agree entirely that something like Leap Motion would be great. I have used QWERTY since 1964 and find tablets to be virtually read-only devices due to on-screen keyboards. Volume / position sensing of all fingers / hands / more (like Leap Motion) would seem to provide the opportunity to replace all on-screen keyboards and be so much more efficient (with the right ideas) that they should make substantial inroads into physical keyboards. I'm not certain actual sign language would be best but something like that has so many more degrees of freedom that the speed and accuracy should be amazing.