From that attack I can move into a kotegaishi or an ikkyo, but not directly into an iriminage. (Kokyonage is also difficult with him) I've asked him to calm down a bit so that I can figure out the best approach to his attack, but even then I feel as though I am not executing the technique right, and other techniques seem to make more sense when dealing with him.
To me it sounds like in this particular case uke's grip maybe has a push, or pull, or twist, that's in the wrong direction for the technique that is being practiced. It might well be that uke isn't even aware of that but is just trying to grip the way he thinks he should. Asking him to grip less hard might not help if the direction of the grip isn't useful for that particular technique. In that case I think it's time to ask a more experienced dojomate or teacher to give more detailed feedback to the uke. Or to give more detailed advice to the tori about how to move into the technique from such an attack.
I've noticed that really quite often "stubborn" ukes are just simply not aware enough of what they are doing to be able to succesfully change their attack to a more appropriate one. Asking uke to lighten up for example only works if uke knows how
to lighten up. That's not a given.
Another example that just came to my mind is this one guy who used to grab in katatedori with an overextended arm and locked elbow. Obviously this isn't safe ukemi since the elbow can easily be injured, and difficult to deal with if tori is relatively inexperienced. It took someone physically moving this guys arm to a less overextended position for him to realize that this is what everyone meant when they asked him to "relax your arm".
My experience has been that sure over the years there have been a few people with an attitude problem who came and went through the dojo. But the vast majority of people in the middle kyu ranks, which is what we were talking about here, are well meaning and just simply somewhat clueless.
It's much more helpful to give people feedback of the sort of "look, your pushing to my outside while you grab, try to push to my center" "let your shoulders stilll be moveable even if you grab hard" "after the shomenuchi, allow your feet to still move, don't glue them to the floor" etc. when they're uke, instead of assuming that ego is involved if uke feels resistant, in my experience.