Instead of having weapon sway for "gameplay" purposes or for hiding AI problems. Arma 3 should try to have realistic weapon sway, which VBS2 does very well.
In VBS2 weapon aim just goes up and down as if you were breathing, then whether you are aiming with the RMB or not you hold RMB and the soldier holds breath for a few seconds, after they pass and you still hold RMB he barely manages to hold the aim and then lets the breath go. In VBS2 firefights go longer because of this and it also requires more from player than just aim and shoot. Really adds certain "oomph" to shooting. Not mentioning that it doesn't make a sniper that "casually lie down and play firing range" kind of guy anymore.