Except at least with Darkfall, there is more than just self-policing. There is also alignment. NPC cities don't allow PKers in, and guild cities can choose to have their guards attack PKers on sight. Obviously in wars between guilds, kills don't negatively affect your alignment. And killing a PKer anytime actually improves your alignment. And you can tell alignments with just a mouse over. I think there is some distinction between knocking out a character and looting him, and actually killing him. Just because you are down doesn't mean you are dead, but I'm not sure how that affects alignment and looting and such.
I'm also willing to overlook the stale visual style of the game since you can design and build your own cities, homes, items, etc, etc. And at least each race has their own completely different feel, so it's not too bad.