Re: commitment vs responsiveness
In everyday practice, I think this depends on the context of what is being practiced at the particular time.
For example, if we're practicing kihonwaza in a set, "kata" fashion, then both nage and uke should be providing proper intent and movement so that both parties can succeed in delving into the form. If we're practicing jiyuwaza/randori, then it's important to hone one's abilities to perceive the most proper response to what's going on and work fluidly and resiliently.
Personally, I think that this ability to perceive and respond appropriately is crucially important in one's development in aikido. However, from what I've felt from high level people is that this ability, in turn, affects one's kihonwaza in such a way that even in a "set" form such as, say, shomenuchi iriminage, there are miniscule adjustments going on all throughout so that the form of the technique is still the same as the basic kihonwaza kata but its content is different than, say, one you might feel from a shodan. In other words, I believe the ability to be able to do a certain technique is very important as well.
To expand the question a bit...
How do you balance commitment in a technique with repsonsiveness as uke?