As one of a few Augmented Reality HUD lua developer for DU I can tell that there is a big need of such functions as:
It could return normalized direction vector in a construct local coordinates
It could return normalized direction vector in a world coordinates
It could return a number that represents a type of camera player is using (for example: 1-first person, 2-third person)
It could really help to sync AR with game coordinates! And make way more great stuff even for popular 3-rd person mode/
Currently at any lag we loose system.getMouseDeltaX(),system.getMouseDeltaY() data so the only way is to reset camera with lockView(1) that is not comfortable to any user. Also we can not make any 3-rd person AR because we can not predict 3-rd person view camera direction on camera switch or even detect camera switch.