Its a interresting theory of the law your making out there. As always players will try to stretch the law in their advantage, and its a reason for the arm in a natural position.
If the ball hits the elbow and forarm(not bounce but like the red mark in the pic under), is that a freekick/pen or is it ok? I bet you would get more elbows sticking out in various positions if that became the law
I do agree with you that I hope they do something with the current handball rule. I dont especially like the natural position thing, because then its up to someone to judge if the arm is in a natural position.