Actually I don't think you understood my point but that is my fault for not being more clear. Personally I don't like the wild throw all your weight and balance behind the punch. While this really does happen in real life folks that attack like this are very easy to deal with IF you see the attack coming. Sucker punches well...just suck, hence the name. Really no technique is needed for the unbalanced attacker, simply move out of the way and they will most likely fall or stumble.
While I have seen the unbalanced overly committed attacker in real life I have only seen one heavily rooted fully karate style fighter. It didn't last long before he got his arse handed to him. He just couldn't move out of the way, nor could he attack with any type of speed or commitment. Having discussed this with a number of others with LEO, prison guards, prisoners, bouncers, street fighters, etc I found their experiences to be similar. While that is not a scientific research project its enough for me.
While I am not a huge fan of competitions (I was in my younger days) they do play a role in training. I not that when watching sparring in the various striking schools I have visited that no one moves like the kata once the sparring gets real. No one plants heavily and attempts to punch. How many of you have heard from striking art students that their sparring doesn't look like their kata? I have many times.
In Aikido, striking art folks will root and plant, simply because they can. They aren't getting hit, nor do they have a fear of being hit by their partner because that isn't part of the technique being practiced. Secondly the majority of Aikido practice is done at a slow enough speed and intensity level that allows the uke to be relatively immobile. Add in the fear of being hit and your attacker will move differently, especially if they have been trained in a striking art that used sparring as a training method.
The answer, and I believe reality lies, in between the overly committed attacker and the grow roots kata attacker. Furthermore I believe you will see the former in real life but not the later. A review of real or sport fighters shows, to me at least, that one needs to be fluid and continuous. One can't be unbalanced, nor can we afford to sit in one place.
As for your comments on distance, I agree striking arts against armored opponents is silly. That was not the direction I was thinking from, nor do I believe that is where striking arts came from. Let a striker that roots close to his distance, once he settles to strike simply move backwards or sideways. This causes them to unroot, maneuver and re-root, before they can launch their attack. Do this enough and eventually they will simply stop rooting and start moving to attack. (Side note: Your hand/arm placement can also dictact whether they throw a straight punch or a hook.)
You wrote: "If you try to lead a karateka, say ala KOTE GAESHI, he will simply drop into a stance and suddenly you're both struggling. "
I totally agree and that is one of the reasons I am not a big fan of the leading version of kote gaeshi. While this is probably an unpopular opinion I feel the leading version, so frequently seen, is really a sensitivity drill, not a technique for real application.
Kote gaeshi works off the principle of rear posture distrubance. In the training hall if uke isn't retracting his/her punching arm after the strike and/or they are overly committing their posture forward, then a leading motion can work nicely to cause a backward reaction leading to the rear posture distrubance and wham kote gaeshi works nicely.
However, in the altercations I have seen or been involved in most folks tend to retract their arms as soon as they realize they have missed their intended target. Trying to pull this arm after it has been retracted or as it is retracted generally ends in the wrestling match you described. However, leading in this case is not needed, as the attacker is retracting his arm he is disturbing his own rear posture (on a minimum of half of his body) and vulnerable to kote gaeshi without the leading motion as a preparatory set-up. Simply apply the kote gaeshi in harmony with uke's retraction. However if one attempts to do the large circular kote gaeshi that seems popular they will be in for a rude surprise. By making the large circular motion they will actually bring uke up and forward thereby eliminating the rear posture disturbance. Now they are back to the wrestling match or worse, uke is smacking them with the other hand. Kote gaeshi works on rear posture - motions down and back, kote hineri works on forward posture - motions down and forward, nikyo will work on either forward or rear posture but not on a person in good posture and balance.
I think I have gone rather far afield with this post. My appologies.