Regarding flinch: Unturned has always had some camera flinch when hit, but the direction was random. Adding direction is intended to make it easier to know where you are being shot from. That being said, flinch on the pitch and yaw axes make it harder to return fire than roll.
So far it is clear that a server option for the third-person recoil multiplier should be added. Intensity and recovery speed of explosion camera shake might need adjusting too.