I think this is great, but doesn't it hinder the ability to naturally not look in the eyes? Or were they just flaws seen in the first demos? I haven't used this kind of system.

In any case, a camera behind the screen doesn't completely solve the problem anyway, because the screen can have multiple people. For this application you need either a camera per person, or the pupil re-aiming postprocessing, to give the illusion of presence.