After playing Arma 3 PVP multiplayer for a few games, which I absolutely enjoyed! This game is going to be my game of choice to play for a very long time, seeing as how excellent it is turning into.
The only issue for gameplay wise in PVP is the acceleration and deceleration of players sprinting and stopping.
In real life, when you are in a full sprint. You cannot stop immediately even if you wanted to. Your body will have to slow down its momentum, this results in you usually taking a few extra steps before you completely stop.
You also cannot get to maximum speed of a sprint immediately when you start your sprint. You have to take a few steps and gradually you build up momentum before you reach your maximum speed.
http://www.youtube.com/watch?v=gUkFDgc7Uk0
Example of character running that uses momentum.
Right now as in game, the player behaves more like a machine than human being. When they choose to sprint, they go at a fast speed immediately, and when they stop, they instantly stop.
During game-play, if you find a enemy soldier standing, he can immediately get into a full sprint. It appears more like a toggle of speed than fluid acceleration.
In real life, if you are shooting at a target that is standing still, you do not expect your target to immediately fly forward into a fast speed. Even if you missed your first shot, you would have enough time to fire another one before he would be able to get into a sprint.
Although Arma 3 does not have melee, if it did. It would be near impossible to land a melee strike on a target if the current system was continued.