What I would find very interesting is what other contributors to this thread think of Yamaguchi Sensei's Aikido in this context.
I think he was a sword master, and generated a tremendous amount of power with completely relaxed arms. I think the countless times when uke's who were remarkably difficult to move would attack him in something like ushiro ryokatatori and their elbows would just pop up due to some imperceptable movement on Yamaguchi sensei's part speaks to his ability in this area. He had his own private dojo and produced some incredibly strong aikidoka in their own right and did not do any standing exercises beyond shin-kokyu and suburi.
Personally, I think that no one thinks that we should develop just enough ki and kokyu to get by. I think people have their own approach to further developing these things from new perspectives. To get to those new perspectives, you sometimes have to shift your focus for a while and look at things in a new light. Bruce Cockburn's "keep kicking the darkness until it bleeds light" is fine when you have a tremendous amount of time - but it also reminds me of the definition of insanity where someone keeps trying the same actions and keeps expecting different results.