I just wanted to point out that sometimes it isn't the teahcer that's the problem, but the student himself. The student thinks he knows the answer before he gets there. As I see it there are two ways of handling this. One is to continue showing the technique as it is, and "hope" that he'll get the point right. The other is showing him the point. The problem I see, is that by showing him the point is that the student really didn't learn it by himself.
And since Aikido has alot of "feel", the only way to be certain of the "correct" understanding is to get the student to understand (to get) the tehcnique. And if the student feels it's the same over and over again, mybe it's because his not willing to learn anymore?