Yes, Yamaguchi was amazing. Peter, you were fortunate to spend so much time with him.
Randori is where I find the most creativity, in my technique, and in other's expression as well. Randori is a mode of communication, much like karate's kumite, or kendo or judo's shiai. No two people express themselves in quite the same way. No two "conversations" are ever quite the same. It is most enlightening to observe and analyze the exchange (the conversation), but it's ever so much better to be a part of it.