Thinking back over the times I've been involved in serious wrist grabbing I was wondering if aikido folks are really ready to have someone grab their wrists with serious intent.
The question is, what is meant by serious intent. Are we talking about grabbing with the intent to restrain? Or are we talking about grabbing with the intention to off balance, neutralize any defense and deliver a secondary attack?
The first choice is basically what you'd find in a non-martial confrontation. Women get grabbed and restrained by someone assaulting them. Police grab and restrain resistant subjects.
The second option is the one which one would find in a martial context in which the confrontation was between trained individuals. Grabbing is a way to take a weapon, it is a way to place an opponent on his edge while striking him when he can't effectively defend, it can be a way to break his balance completely and take him to the ground, normally followed by a strike, kick, or potentially moving to grappling range.
The big issue with Aikido is that the vast majority of folks practice grabbing as the first option, which has little or nothing to do with how grabs function in a martial encounter. The first thing anyone from outside Aikido comments on when they see Aikido is that no one attacks like that.
Katatetori and all other grabs in Aikido should be trained from day one as balance breaks, not restraints of movement. If you can't take the guys center with the grab, or use the grab to defend against his strike with the off-hand, your are not grabbing effectively. If you are turning your partner's hand purple, you are putting your energy in the wrong place. I would especially like to see expunged the idea that a committed attack is one in which you push the nage;s arm into his body. I don't know who thought that was good attack but it invariably puts your face right where my atemi can hit it easily. It's just bad martial arts. Only Aikido people will try to deal with that with some cool movement. Everyone else will simply hit you with the other hand.
When people understand how to use the grab as a way to effect nage's center, then we can agree that uke doesn't actually do the balance break so that nage can practice his techniques. Later, nage needs to be able to do his technique even if uke is trying to break his balance at the instant of contact.