my answer is a no, regardless on if its an instant kill or just higher damage shot, this just isn't that time of game. A real time FPS that allows control over the gun, sure, but we cannot even target a specific player, let alone specific body parts. The only way some idea of the sort might work to me is using Stances and a targeting system. The duel approach to stand straight up and increase shot accuracy, while reducing your ability to dodge. That would also mean allowing a crouch and some form of targeting the head or body, changing the FF dynamics entirely which is a 50/50 on if it improves or hurts the game. But at no point should there eve be a one shot kill. One shot kills are a great way to push people away from FF'ing. Buffs, travel time, having to ask for rank and be online all to get killed first round as a premium tank? The odds of it happening may be 1 in 100 battles but you will be furious that one battle and for some it will be enough to walk away.
