Thank you. Don't get me wrong, I'll murder people if I think I stand a chance. When you decide to kill a guy running through the streets of Reno, it's the most exciting thing you can do ingame. Especially when don't know you're going to win. But there's a difference between that and shooting people you know don't stand a chance. (I'd also suggest that fights where you don't stand a chance are the biggest turnoff to new players)
If you start the fight unprovoked, you get a karma penalty. If the guy has less kills than you, you get a karma penalty. If the guy is several levels below you and didn't start the fight, you get a hefty karma penalty. That kind of thing. Just something that will make people think twice before gunning people down. If you behave like a psychopath, people start to treat you like one.
Obviously, TC capture time means nobody gets flagged. It'd be too hard to fix.
PKing people is very lucrative in the game - you get guns and gear instantly. Which is fine, but like the crafting timeout, there should be a penalty for stealing it rather than working for it.