The thing that most of you have not mentioned (I don't know if it is lost on most of you or not) is that the Con damage ALSO does hit point damage by lowering the subject's Con modifier. This is why I like Con damage for massive trauma of all kinds, and why I am considering it as an alternative to Vitality/Wounds for a more "realistic" critical damage system.
You see, when you take massive trauma, you're less able to heroically dodge all those sword swings (or bullets or blaster bolts or whatever). It beautifully models what happens when you fall and break your leg, while remaining (essentially) "abstract".
I haven't ever gotten my own system worked out on "paper", but I would like to point out my own ideas on the subject:
I think the damage per x distance should be gauged so as to be potentially deadly to a tough hero at about 40 feet, and VERY deadly to anyone at about 60 feet.
Then, in keeping with the heoic fantasy (and to satisfy whiny players), there should be a Reflex save for half the Con damage. So, the freaky fantasy heroes can fall "unlikely" distances while SURVIVING, but they still limp away. AND there is a built in limit to that survivablility, i.e. when half the damage is more than your Con, your dead anyway.
I should point out that I also favor 0 Con= dying not dead, but then I like dying to be deadlier than RAW.
Thanks for reading.