A moment of insight: I think one of my obsessions in game design is to de-familiarise violence.
Most computer games involve violence, but it's almost never presented as something problematic. You kill, because killing is what you do in a computer game. Who cares about all those bandits you slay in Baldur's Gate? If reasons for violence are given at all, they just serve to hide te problem of violence even further. You fight the NOD, because they are evil, and surely you must fight those who are evil. You fight the GDI because you are evil, and when you're evil, you fight. No problem. Even in a more sensitive game like The Witcher, most of the killing is not made into a moral problem: you're just killing monsters, right? ("Monster" now has the moral value that was erstwhile carried by the word "brute".)
So what I have been trying to do is to take violence, put it in my games, and yet make it a problem. Nothing is more standard in a roleplaying game than having to kill a wild wolf when you travel through the forest; but when you attack the wolf in The Baron, you must leave her child to die of hunger. (Well, there are some other options, none of them pretty.) In the game as a whole, violence reveals itself as self-destruction.
In Fate, violence is an answer; but it is not therefore morally justified, and much is made of this. Also--all the problems that exist are the result of either past violence or intended violence.
In my roleplaying game Vampires, violence is the only way to survive. What is more: the only way to survive is by doing violence against defenceless women that actually disturbs your audience--the best wat yo secure your continued survival is to make the other players think "I don't want to play this game any more!" when they hear you describe what you do. In Vampires violence is so ugly and unredeemed that the game probably cannot be played. (Except in the way I described in my spoilery essay on the game.)
In my (not ready to play) roleplaying game Stalin's Story, one of the players is given the authority to arbitrarily command the other players, and he is put into a situation where doing fictional violence is necessary. Here, violence is problematic because you do it against the other players and there is not even the semblance of a fair contest.
In my best roleplaying game, Shades, violence is less foregrounded; but it is always there in the background. This game is about reflecting on past violence, about coming to terms with it, resolving it It wouldn't be much of a simplification to say that all the rules have a single aim: to make the social situation of play as free from violence as possible, while making the player think about how violence could enter their lives and how they can overcome it. The Baron and Vampires are about kicking people in the groin while they are sleeping; Shades is about reconciling people with their awakened state.