My dream tech regardless of what area it's applied to is close to that. "Hard light" holograms, if at all possible at any point in time, would change so much of society it seems funny to consider the tech premiering in video games.
Augmented reality, through the use of lightweight glasses, could be a nice proof of concept though.
I don't necessarily think it's funny to see that tech premiering in games. When 3D got really popular it wasn't possible to use 3D TVs without those expensive glasses. Nintendo was able to do real glasses-less 3D and then was able to improve on the concept. It amazes me that more companies haven't tried to do glasses-less 3D screens.