... unless you're engaging in martial arts as a business, the student is responsible for keeping their own mind engaged in their practice.
I do think there's a certain responsability for a teacher that sees themself as an educator to present the subject matter in a way that does't put people to sleep, but it's still the student's responsibility to give the interest and attention necessary to stay connected.
I understand, and essentially agree. But I see the teacher/student relationship as a contract, with both parties required to do things to keep the relationship going. On the instructor's side, motivating the student can too easily degenerate to pandering, but I'm talking about something else. Students don't know; that's why they are students. So what we do isn't always what they think we are doing. I am reminded of an old Castaneda quote, "Only a fool would voluntarily seek the path of knowledge. A sensible person must be tricked into it." Aeschylus, I believe, said something similar. This speaks to what you said about not putting people to sleep. Another old saying has it that, "There's a whole lot of difference between making people laugh and keeping them from crying." A similar gulf exists between keeping people awake and not putting them to sleep. I've never had the honor of working with you, but from what I've heard, you are more on the keeping them awake side of things. That is, you aren't just standing up there and handing out information; you are more likely engaging the troops, and leading them to interesting places.
What I was trying to get at in my first post is that the style of teaching is as important as the structure, that a small class is best made use of by an instructor who can amplify and steady and steer the students' enthusiasm. The big-numbers dojos that I have been in suffered not just from infrequency of direct contact with the instructor, but from the hierarchical attitudes and personal isolation that that context tends to favor.