As it is now, when critically hurt, the player will be forced to walk as opposed to crawl like in previous Arma games. This is very good as you still get that feeling of being very hurt, but you are not that stuck anymore.
The problem is that when the player get critically hurt he will not fall down anymore. This is both less immersive and very dangerous as you are often stuck walking and will die before being able to do anything.
So when taking a bullet the player should fall to the ground imo as it was in previous Arma titles(this is a very immersive experience), but he should also be able to stand up and walk like he can now in Arma 3.
The key difference here is that he actually falls when being hit, otherwise the system is perfect as it is now (although seperate walking animation for being hurt would be awsome :D but im not counting on it as I know this is a lot of work)