Yeah, it would be cool. How it works is the damage you get when you fall at the hight, minus your fall breaking bonus, so that way, if you're trained to and on your feet, theres less chance of dying. As for jumping, I think a good idea is if you jump down 3 metres, there will be no penalty, but the health loss begins after 3 metres, though like I said, enkis have a bonus in fall breaking (I think they would) and maybe there can also be a jumping skill, the higher it is, the higher you can jump? (it couldn't go up too high though.)