I certainly agree that anyone committed to his or her art or craft would learn after 20 years. I know I have! However, what I am saying is that I (and may others) have still seen him demonstrating techniques in a way that is consistent with the quote from Aikido and the Harmony of Nature. In other words, the majority of what he demonstrated from what I have seen is consistent with that. As I said, sure, he has shown other things that could be described as "tricks" but they are the minority in my experience and could hardly represent a paradigm shift brought about by some new insight into IS. He has explained the exercises were for pretty consistently.
It just basically comes down to how one defines "Aiki" and what I am saying is the vast majority of what he is demonstrating from what I and others have seen and experienced is consistent with the quote. I would certainly not say that what he is doing had not evolved just that it is consistent with the Aiki as he had defined it which is the blending of energy. At least that has been my experience.
http://www.youtube.com/watch?v=fjk_cLB8yHw
http://www.youtube.com/watch?v=F97kmNs8IiE
Train Hard,
Jason