I've been trained to be aware of openings to counters, and I have trained myself to be aware to what extent my uke is choosing to take ukemi or going along with what I want them to do; the thing with uke holding on is a great example, I really hate that and I strive to minimize that. I don't think this is rocket science at all. You just have to be honest with yourself about who is responsible for the ukemi, and learn how to feel what is going on.
I totally agree with the honesty remark. As to this being the mechanism for self-correction in transmission of the body of knowledge that is Aikido, I don't think it does the job because it absolutely depends on the student.
To my mind Judo, has more of the self correcting quality where the basic waza is laid down by the Kodokan and pretty much everything else is enforced by the competition rules. As long as the rules don't change the art will not change that much. When rules are modified, the practitioners will adjust to optimize their Judo with regards to the new rules.
This is just an example, I do not claim that adding competition to Aikido is the way to go.