mmk tried it out it's cool that they implemented it (Although IMO too early in beta to add this feature better things could have been included first *cough* lock and key system) but the damage is way too high as it stands for such little falls, I've scaled mountains on trips and you can jump pretty far without actually hurting yourself if you know what you're doing. Currently just walking off a standard rock takes half your health.. and breaks your legs.. while I remember being 6 and playing on rocks that size with ease.
At the same time, if you don't know what you're doing you can break a foot on a relatively short fall. I have a vague memory of when I was much younger jumping off a back porch and landing wrong breaking 3 bones in my foot. Taught me very effectively to not land on my foot that way again. =D
That being said, breaking my foot didn't leave me half dead and wouldn't have killed me if I jumped again landing the same way...