"the one need he refused was external validation."
what a fine line to balance... I can imagine someone trying to learn through this credo and some of them would probably go through the process believing that their way is correct until proven otherwise. If by any chance they are stronger or more assertive than their ukes, it is likely that that time would be pretty long indeed. Unless of course the sensei comes and shows them the error of their ways.
I think a lot of soul searching is needed to improve your aikido. But sometimes its frustrating about thinking you know the theory behind it, but you're unable to do it. Its like this switch or key you're missing that is not visually available from your observations of sensei's or yourself.