I dont think KOS is a problem, but If I may suggest a "solution", how about more options on the combat system that are not lethal? Dont get me wrong, a headshot would still kill, but, maybe, a combat system that allows players to shoot the legs or just hit (with blunt weapons) with the purpose of knock down another player, not kill. Of course some people would still kill, but many others would just stole the loot and let the victim go.