Re: uncooperative, overbearing....
Peter I totally agree with your post. I would wag (wild ass guess) that George does as well.
I think the following paragraph of yours is one of the best and most succinct I have read on the topic, hence it is worth posting a second time.
Peter wrote: "It is the role of the senior student in a pairing to define the appropriate level of resistance. In kata it usually is enough that tori has something to work with, can understand the mechanics, and most importantly understand where he is going wrong. Too little resistance is unsatsfying, too much is frustrating and ultimately unproductive. Usually uke is reasonably close so no problem but sometimes he is wrong either because of inexperience, a bad guess or (and I think this is what the post is all about) because they are an ass."