This looks slick! The current edit mode is confusing and one presented in the video is a such an improvement and better user interface / experience. With it, I can finally introduce this concept to my brother.
I guess the main improvement is that the panels and sidebars don't cover the desktop, so you can edit all of it more easily.
To me the most annoying thing with edit mode was that auto-hide panels would still hide in edit mode, making them difficult to edit, but that was also fixed a little earlier.