I'm currently working on a new AI mod and having this feature would be very useful. Unfortunately, the command playMoveNow seems to override the aiming behavior of the AI while the animation is still playing (if looped, during the first iteration, see https://feedback.bistudio.com/T144528). So having a manual setWeaponDir command (and maybe even head direction?) would be useful.
P.S: I'm not sure why there's no such feature in the game right now. If it's because people might be able to create aimbots and cheat with it, then I'm sure you know better than me that there are hundreds of other (and more effective) ways to cheat!