You must give 'trolls and rule-breakers' some incentive to leave. Trolls and rule-breakers will not just leave because you ask them to politely (or firmly for that matter), you cannot supply them with the powers to be rule-breakers, or you are just tempting them to break the rules. Also, I'm not neccessarily saying that you have to absolutely remove buttswing from the game-just that it is not an idea that you should throw away. What you are saying is you are going to supply them with ways to break the rules. Even if you ban them, they still just make another account and continue with evil deeds.
Also, I'm not saying that no one uses it appropriately-I have never seen someone use it appropriately, which does not, like you said, mean that no one uses it appropriately. I'm all for not punishing all for the crimes of the few, but this is not the case in this situation.
Also, no it would not be like making blades blunt so murderers wouldn't stab others-I'm trying to take away the blade so they can't use it in the first place.
Also, about the headbang and crouching and sitting-I don't believe you should take away crouching and sitting. The point of taking away buttswing is because no one uses it for appropriate reasons-and since I believe that you should not punish everyone for the deeds of a few, you should not take away crouching and sitting because they are normally used for the intended reasons.
Headbang-
You could do this with the buttswing as well, too, but instead of completely removing it from the game, you can alter both the headbang and buttswing so they do not act so 'inappropriately.' Like I said, I am not making it mandatory for you to take these things away-I'm not making it mandatory for you to do anything at all, I'm just stating what I believe.
For example, you could just make the head bang instead of both the head and posterior. For buttswing-you can turn it into a back-flip or a roll an action such as that.
I understand you're not trying to start something, and I appreciate that because I don't want to get into a full-blown argument over something as silly as keeping in a simple animated dance move. You do not have to argue against me, for I am not trying to force you think as such. You may believe what you like and do what you like with that game, I am stating what I personally believe, so I am not saying you must believe that, and if you would respect that this is my opinion as well I would greatly appreciate it. The only reason I argue back is to avoid mis-communication between two people, and to tell you my own point from my perspective. If you don't want to listen, that's fine-I'm not forcing you to read what I have to say.