My bad on that math part. Only had like a minute to make a post and it was early morning, my brain read HS/Shots * Hits/Shots which is why it didn't add up.
Yes, not all weapons perform them, this is true. However, for weapons that don't use headshots, there is less skill involved in them. Do you think you should get as much rating for a hit with a panzer than a headshot with a luger?
As for my formula, it seems I have forgotten Occam's Razor, or at least the inaccurate summary of it. By multiplying damage (Later became Damage/Time) by your aim percentages, it guaranteed that trying to get good hs/acc will always benefit the player. If it were static, Players with high damage would be relatively unaffected while players with low damage would do better by trying to never miss a shot, rather than trying to kill people. Seemed good, but there is a problem. That will give more of a bonus to players who are already doing better. The Damage_Recieved/Damage_Given does the same thing, and though I had an idea to fix it, I may get rid of that one as well, even though it helped aggressive strategy, because it also gives more rating to players who already have more rating. While this itself wont break a rating system, I would rather it be a more simple formula.
As of now, I am thinking more of this simplistic idea:
(Damage_Given - (.5 * Damage_Received)) * (HS / Shots)
This gives a problem still of messed up ratings from never shooting, or from never getting a headshot (although even the worst players seem to always get many accidental headshots, it cannot be assumed they always will). If anyone can think of a more elegant solution than HS + 1 and Shots + 1, please contribute.
Also, I feel this still encourages camping too much, I need a better way of handling damage received, so that there isn't a disadvantage to playing aggressively.
Still no time to start testing numbers, for now its still a thought experiment.