Took a a look at that thread and while some proposals seem unnecesarily complex, what pressure (PEER) suggest seems the simplest solution, since MoI3D is not intended to be used exclusively by command anyway. It would certainly be a noticeable improvement over the existing approach.

You could even leave this for a toggle switch in the options, so it's up to the person to decide if using absolute angles as until now or switching to relative angles.

Another option might be using some kind of reference hinting, like Sketchup allows. But this would probably take more time to develop.