Your talking about punishing unintentional tks as well?
That's just plain dumb. We already have a vote kick option that, if you post a reason, and it's obvious the person is tking, then they will get kicked. Or admins will do it. There's no need to put in a system that will punish purely accidental tks, because, lets face it, we get a lot of them. The majority of people apologise straight away. Anyone who does it to me always apologises, as do I. Even if I put 1 arrow in someone I apologise, even when it doesn't kill them.
You also can't compare this game to other MP rpgs. What other rpgs are in reality a first person medieval warfare game with even a similar system to Warband/cRPG. I can't think of any.
If someone is obviously trolling ect, then the current system means they will get kicked. If you can post proof of it, they will serve a ban. I think that's a fair system. Any in built system will quickly lead to protest by archers, HA, 2h, polearm users, hell, anyone who is liable to accidentally tk.
Be polite. Apologise. Accept an apology and be gentlemen. Even if it's a stupid mistake. Otherwise, intentional tkers will get kicked/banned.
As MrShine says, cRPG is a relatively small community. If you get banned on a server, you only have limited options as to where to go after that. Either you play in an empty server on your own, you join another server and play properly or you get banned from all of them. He also makes a good point that putting a gold value on it cheapens the crime. A small gaming community like cRPG can put enough pressure on trolls to make sure they don't hang around long.