Looks like preserve-3D support is "in development" for now. I wish there provided more visibility that that.

Why don't they at least say which version of IE they expect that to land in? Does that mean IE12? IE13? Some minor bump of IE11?

WebRTC not planned? This is just another confirmation that as a web developer Microsoft will always be my worst enemy. The reason they don't support WebRTC is because it competes with Skype.