Google glass has a really small display on the top right of your right eye. It can overlay maybe 5% of your total field of vision. You cannot even see your hands through it unless you put your hands at a particular angle and distance. The small display is not enough for overlaying the complete field of vision. Why is it so small? Why isn't it a full blown glass with full augmented reality? The answer is power - even the current model of Google glass barely lasts 3-4 hours after heavy usage. With a larger screen, it would last less than couple of hours. So yes, these Minority style stuff is cool and Google is aware of it but they won't happen unless we solve the power issue.
Disclaimer: I work at Google and I wear Google Glass almost all the time.
Disclaimer: I work at Google and I wear Google Glass almost all the time.