Good ideas - we've considered these as well actually!

The intertia-idea wouldn't be too difficult to implement, but its usefulness would probably depend on the application area.

Yep exactly. Usually it locks onto one person's face but it can also jump around, so there are still optimizations we can do there - but generally it's supposed to be for one person. If you compare to VR headsets, two people can't wear the same VR headset anyway!