Kuroiwa Sensei .. some very good points there, but I think his view of kata is very different from Mochizuki Sensei's traditional view.
Your main point is this, I believe:
In mainstream aikido, ... two sides are performing interlocking roles that leave one standing and the other on the ground. So the whole practice is kata.
However, in the old aikido, that was not how it went. You would learn through form, but the training required actually applying a workable technique to a vigorous attack, as in all jujutsu.
Kuroiwa Sensei is, of course, correct in the context in which he speaks, but in the real traditional martial arts context, those comments are less comprehensive.
Here is the pertinent comment IMO:
Kuroiwa interview wrote:
Yin practice is the expression of "shackled" form. Thus, it is first necessary to be shackled. It is important in training to correctly understand the roles of "uke" and "tori". Uke's role is to adjust himself/herself to the movement of tori and tori learns his/her movement with the cooperation of uke. Failure to understand this will lead to the misunderstanding that uke was thrown or pinned because tori's technique was excellent. Uke absorbs the movement of tori with his body by taking a pure fall. In other words, uke is not thrown but rather is practicing a form in which his role is to be thrown. Thus, the central character in practice is uke. Usually, in the case of fighting match, the first requirement is not to succumb to your opponent's attempt to break your balance. To have lost one's balance means to have been defeated. In the practice of Aiki, as uke we unconsciously assume that having our balance taken is a good thing. Here exists an important principle and a danger of yin practice. Unless one understands this (i.e., uke and tori are aware of this), practice is meaningless. ... A certain degree of Intellectualization is possible after recognition of this agreement. Otherwise, this merely leads to conceptual games and self-satisfaction.
In the film The Outlaw Josey Wales
he said to the Kid "Now remember, things look bad and it looks like you're not gonna make it, then you gotta get mean. I mean plumb, mad-dog mean. 'Cause if you lose your head and you give up then you neither live nor win. That's just the way it is." The whole film is about Josey essentially running away from things that are looking pretty bad. Overall, th posture of the film seems very yin, but in close detail it is exceedingly
yang. That's why it is a great bit of mythology. This kind of perspective is, I think, allied to Kuroiwa's point.
Ukemi is not "giving up' it is playing a role, with an eye toward requiring
that one;s balance be taken and then following where it is taken
to be able
to see the natural point of reversal without the desire for it obscuring it.
There are two errors here, really: one is a commitment to a mindless, dive-bunny yin -- the other is refusing to surrender to the yin and try to maintain yang at all costs to avoid ukemi altogether. Neither one is correct.
The nature of things requires that before one can reattain strong yang one must fully
the yin state. It is not the amount if time spent in yin or yang that matters but rather the COMPLETENESS of acceptance of each in turn -- which therefore always includes its opposite regaining the priority of action in due course.
This is not a passive adoption of a sessile yin nor a vain scrabbling after a slipping yang but accepting both yin and yang in their proper orientation and roles.
At least that is how I see it and Kuroiwa's comments seem in the same neighborhood.