George S. Ledyard
What Ikeda Sensei, and the rest of us, got from Ushiro Sensei was an organized set of explanations that made many of the elements Saotome Sensei had always had but did not explain, clear as discrete pieces that could be looked at and worked, distinct from other elements. Saotome Sensei largely just did stuff. Nothing was ever pointed out.
As someone who has taken ukemi from Ikeda Sensei for 35+ years, I can say that, while the outer form of his techniques is much the same, what he is doing is on another level and the experience of taking ukemi is quite different.
I wonder if getting the organized set of explanations from Ushiro Sensei not only gave Ikeda Sensei the tools to point out specific things, but also put him in a better position to explore and refine his own technique in a way that resulted in your experience that the ukemi for his technique is now quite different.
That has certainly been my experience in recent years seeing Ikeda Sensei; how he presents things now has put me in a much better position to refine and develop my own technique more effectively (even as my body has become "worse" from the progression of muscular dystrophy). I have had similar experiences in other areas of my life, where being given better tools to explain/present something not only helped me communicate better to others what I wanted to say but also changed the rate at which I could improve.