Great question...interesting...the work of Homer Kelly is a really incredible piece of work that took in reality a lifetime...if not...at the very least....it was a lifelong journey once it started. It is well documented that he himself continued to update and improve on his work...and from what I gather from people that actually spent time with him...they have confirmed that. He put the geometry and physics of the swing in a format that is quite astounding during his time....every time I look back into the book...I see something new and in a different light. The mystery continues to fade away as I read and understand more. I enjoy using the book as a source of information along with other books written before TGM and shortly after. It is a book that has definitely assisted every accomplished teacher walking on this planet with his or her core knowledge of the golf swing. Either directly or indirectly. Armed with this core information and the desire to learn, teach or play...you will be better equiped for the journey....but remember....this does not guarantee that you will ever become a good player or student or teacher. Communication is the key and how you communicate the core knowledge to yourself (implement) or as a teacher to your student is the the "Secret" if there is one.
To guess what changes should be made for an 8th Edition would purely be a guess and really has no bearing on anything with respect to the information that Homer Kelly has given us. If he were alive today it would be interesting to see what progress he could have made...we..unfortunately don't have that luxury. Great conversation though.
I think that "YODA" could be the best connection to the past... walking today...that could best sift through how Homer Kelly would have developed the later editions 8th....9th....10th.....and on.
I would highly recommend a visit with Lynn to anyone that wants to get "the rest of the story".