How about including the progression from Basic to Acquired to Total motion? Seems to me that would be very accessible and is a great way to start out students. It would be a great example that would be instantly applicable within each pro's own teaching.
As someone who is an experience golfer but TGM newbie this would clearly get my vote. This is one of the toughest things to fully comprehend, but fairly easy to digest. I believe a lot of non-TGM teaching pros would benefit substantially from a better understanding of this concept.