I've been thinking about ideas for a 'kill factor' metric before I ran across this poll. Note that I'm only considering player statistics and not in-game rewards, since those are a different kettle of fish.
Essentially, replace the current "kills" stat with "deathblows" and award them as-is, because people will want to see it.
Kills would then be weighted as a factor of your damage compared to the total damage inflicted on a target, so if they die and you inflicted half the damage they suffered you get 0.5 kills.
Then, if you half-kill two enemies (and they subsequently die) and die once, your kill/death ratio is 1.
If you inflict 99% of the damage to an enemy and someone plinks them with a machine gun to "steal" the kill, you still get 0.99 kills.
If you "steal" a kill by plinking a critically damaged enemy with a machine gun, you get 0.01 kills.
This would remove the potluck element of kills where multiple people are firing at a single target and all contributing, but only one person is actually awarded a kill for it; effectively, you'd be letting assists contribute to kill stats.
You could also compare your deathblows to your kill factor; if your deathblows are comparatively low you're getting a lot of assists, if your deathblows are high perhaps you should consider contributing more damage overall rather than just finishing people off.
It's not entirely perfect; if someone splashes, say, 150 damage all over an Atlas whilst missing the head and then you kill it with a perfect single headshot, your kill factor is reduced even though the splashed damage didn't actually contribute to the target's final manner of death. This is probably not a huge factor, though, since generally every point of damage makes it easier to kill a target (if you missed his head his torso might have exploded anyway). Arguably it promotes kill stealing by pouring massive amounts of damage into a target, but, uh, shouldn't you be doing that anyway?
EDIT: I've possibly misinterpreted the word "weighted". Oh well.
Edited by Gejaheline, 29 April 2014 - 06:46 AM.