Ars Technica has published a critique of the Glen Keane VR demo for the Future of Storytelling event.

Apparently Keane's video was somewhat misleading in avoiding the 3D aspect of the technology because of the distortions that result in the drawing. From the article's description of using the HTC Tilt Brush, the VR drawing system employed by Keane in the video:

"Not only is your stick person floating in three dimensions, with your every splot of paint enjoying its own X-, Y-, and Z-axis properties, but its parts are probably all floating at different points in the air. You've just drawn on something that has no solid stopping point, probably for your first time (unless you're a sky artist, in which case, we'd love to chat). And we guarantee that if Keane was seen really walking around his creation, it'd have some very weirdly hanging eyes and other details."

These criticisms might be spurious though. Decide for yourself by reading the article:

http://arstechnica.com/gaming/2015/09/how-a-disney-artists-deceptive-vr-demo-still-heralds-a-new-
digital-art-future/