Present Recoil System sends the players aim lurching upwards with no return to center.
In reality recoil from firing rifles or machine guns for many years in the Armed Forces taught me that the recoil from these types forces the weapon back into your shoulder, when using a scoped sight the recoil causes an intense vibration effect when looking through scopes, not the huge jump upwards that we currently see.
To create a better recoil simulation, a very very small "jump" with immediate return to center, with intense but very short vibration effect throughout would yield a very accurate and enjoyable experience.