Don't disagree with anything you said.....but this is one is an extremely easy fix, IMHO. Ball thrown with both hands (with already noted exception for physical impairment). Neither hand can be behind the ball during forward motion. Or if hand placement does not matter, ball thrown with both hands touching the ball.
I really don't care if a hand behind the ball is legal or illegal. It should just be stated clearly.
I am just going to continue to poll refs at our games to get an overall sense of their understanding of the rule because I think it is interesting. I will place my results here for anyone that is interested in seeing them. If you are not, then don't look. It is really that simple.