My broad impression, after 3-4 days playing around and watching and practicing his vids, is that the thesis boils down to this:

If you use all the muscles in your legs and hips, with gradually increasing ROM, for 3 months, then good stuff happens.

It also doesn't seem to conflict much with what most people do in the gym. It does a bit with my running hobby - my lower legs are a bit overloaded right now - but I read the program and just knew right away that this was stuff I should have been paying attention to for the last few decades but haven't.