I attended a seminar by Clarence Chinn sensei where he spent a lot of time critiquing our attacks and asking for more committed attacks. He defined a committed attack as one that would make nage want to move out of its way.
He chose to drill this with kata tori, which surprised me since there is no intent to damage--you're just grabbing uke's shoulder. He asked us to do kata tori in such a way that nage would be impelled to back up. This is certainly paradoxical, and when we started we wondered if it could even be done. Why should nage back up for kata tori? It won't hurt if it lands.
I found this fascinating to practice, though very difficult. When another fifth kyu and I were working together, we found that the attacks which could actually make nage back up were recognizable as such as the moment they were initiated. If nage didn't feel inclined to move from the start, he wouldn't move no matter what uke did later. Uke could lunge with great energy, kiai, make fierce faces, even hit nage and it still didn't work. (Later in the seminar I accidentally stomped on our Head Instructors toes and he didn't move, though I guess he wished he had.) However, there *was* a way of moving initially that would lead to nage backing up.
As nage it felt as though you'd been momentarily distracted from your goal of standing in place. We worried at first that we were moving "on purpose" but with practice it became clear that the quality of uke's initial movement determined nage's response.
Chinn sensei could turn this on and off at will and it was fascinating to watch the senior students practicing with him as they got out of his way despite their intentions, or didn't get out of his way (when he was deliberately not making a correct attack) despite speed and apparent energy.
I think the kata tori drill was great for showing what he meant without the complications of a possibly harmful atemi, and I'd recommend it. All of us below dan rank seemed to find it quite challenging--I'd sure hate to have to do it for a test. It was humbling to realize how weak my ordinary attacks must therefore be. (I got an extra lesson in humility by being asked to be sensei's uke for a demonstration of "How do you handle a beginner who cannot give you an adequate attack?")