I'm in complete agreement with Larry et al on this one. There are way too many openings in the technique to begin with.
Pain compliance - if that doesnt work, follow it up or start with some heavy atemi.
Apart from a few obvious problems in the execution... One pet peeve of mine...
There is a difference between simple pain compliance and injuring someone. And you need to understand that difference. Pain compliance can work with a less than motivated, inexperienced or not really that angry attacker. But when the adrenaline is flowing pain compliance sometimes goes out the window. FWIW I ran to help a victim of a horrific car accident years ago. I got out of my car, ran over to him, and put my shirt on a really bad head injury the guy had until the paramedics got there. Once they got him stabilized another paramedic came over and said "we'd better take care of you now". I was confused. I told him I wasn't involved in the accident. He then sat me down and lifted up my feet. Oops. I wasn't wearing shoes and I had run across both broken glass and some sharp metal. My feet were just ripped up and there was a chunk of a beer bottle sticking out of the side of my left foot. At that moment it suddenly started to hurt. It hadn't hurt before. Or I didn't notice it. Or whatever. But at that point it was a sudden rush of pain.
So that said remember that pain doesn't motivate everyone. But there is a huge difference between "ow, that hurts" and "snap -- you just dislocated my shoulder!". When you're twisting a wrist/arm in a nikyo if you continue hard and power through you can damage to the joint itself. Many pins are just a hair away from a dislocation if they are continued. The continuation of many of these joint manipulation/stressing movements goes from pain to injury very quickly.
When we train cooperatively we tend to stop after the start of pain but before the start of injury. That's a good thing in that we want to be able to train some more. We'd run out of training partners really quickly if we didn't stop. But you need to realize that if you're using some of these things "for real" you may need to continue. They may resist. Or the pain may not register. They may push back, damn the torpedoes and all that. It would be nice if people would just give up automatically, but if they don't, are you willing to continue and tear apart their wrist? Or in a pin with them face down and you have their arm behind their back are you going to be willing to dislocate their shoulder if they try to fight out of it?
I've tried some of those things in the video over the years. But my view of it is trying to understand how you're going to deal with that situation. There are no shortage of brutal solutions to someone trying to reverse those techniques, but many in Aikido are conditioned not to go that way. But with anyone else, well, it is flat out stupid to try something like that. If you're going to resist the nikkyo and I've also gotten into that position without managing to have an advantage in balance and positioning (all issues in this case) my choices are 1) let you reverse it, 2) change technique, 3) put on more pressure to hopefully motivate you not to do that, or 4) put on more pressure then finish it and bust up your wrist if you're too stupid to realize just how vulnerable you are.
That said I can think of a few people I train with where a reversal like that might work with them. They're much too nice and some have bad habits in their applications.
There are others, however, where trying something like that is just not a good idea. I don't need to spend a month with a swollen wrist in therapy...
One great thing about aikido is that we can train in a "live" way. People try to hit, try to grab, try to move you around. We have a set of means of dealing with protecting ourselves. The drawback of that is that we tend to stop short of certain things (for good reason). I don't routinely try to break wrists. I don't dislocate shoulders. So while someone may find that they can reverse a technique, you need to ask yourself if that reversal is possibly only because they aren't willing to just rip apart your wrist. Or dislocate your shoulder. I had a wrestler friend who could wiggle out of a pin I had him in. He was really proud of himself. But the reality was that I wasn't willing to dislocate his shoulder to keep him from wiggling out. Yes, it starts as pain compliance -- the pain at first is the signpost that the joint is close to sustaining a considerable injury. No, I couldn't hold him down with leverage alone. But one small twist and shift and I would have ripped his arm out of the socket. He's my friend -- I'm not going to discloate his shoulder. But a bad guy who has just attacked me and my family? If he tries to get out of that pin, well, I'm going to make sure he doesn't get out. Or if he does he's not going to be able to use that arm again... Ever.
So ultimately, how useful is a reversal move like that? It'll only work among cooperative people who are trying very hard not to hurt each other. But if one really does want to hurt the other... Different story entirely.