Re: Locking/pinning as pain submission...
A couple of comments;
I agree that overemphazing the pain aspect will lead to crappy technique. In my opinion, at the beginning stage pain in the joint techs should be a kind of stretch. A person's wrists will get a lot stronger through joint tech practice.
Past the beginner stage, I feel that working with fear is extremely important. Pain is an excellent way to start to deal with it. I just watched a tv program on a martial art they are calling chanbara, working with padded swords and a helmet. The point is that one can practice really hard and no one gets hurt. I think it is excellent but the lack of pain means the lack of fear which is detrimental to progression in the MAs.
I completely agree with Bryan on a soft grip. I just think that it is important for beginners to overdo the grip in the beginning and then soften up. They learn the feeling of a relaxed powerful grip better this way than the opposite. Also, at a higher level, giving your partner a strong grip to resist is a good way to set up henka waza. The late Tohei Akira Shihan often showed techniques from nikkyo.