Both interesting points.
Neeraj, you might like
this blog posting, which says in part what you are saying. I'd have more to say in response, but this article overlaps my thoughts well enough to dissuade me from further comment.
Ilja, you've hit on a point I'd like to develop and say more about. The biggest difference between a book (be it reference or learner) and a course guide, in my view, is the assumption that one does a better job of
contributing to the classroom experience, if only because one of them tries to, and the other doesn't.
One might think that some authors with classroom training in mind would factor this in to course guides. I don't see a lot of that, and in my time I've taught from 50+ different course guides, not even counting major revisions among them.
I'm not talking just about dry, tech-transfer type course guides either. It seems to me a good course guide does two things at once. First, it presents a loose but coherent narrative that allows the student to see clearly a sustained build of ideas, a natural flow of topics. From that, it seems to me a sense of well-being that there's a plan (and a good one) will follow and so the student has every reason to stay engaged.
Second, the guide persuades the reviewing instructor that the plan is good enough to help them do what they do as teachers. That goal is a damn tall order, I'm here to tell ya. Part of my current kicking and screaming stems from trying to fix and update a spaghetti mess of an existing course guide. Given the time I have, there's no way I'll make it into something very good. Better, sure, but not worth the price they charge for it. There isn't enough calendar time to do the work, and I can't work 50 hours every week just to try and cover the difference. (Not on this kind of material anyway...)
And on particularly specialized topics, I suspect instructors want the course guide to be as completely behind their experience and desired presentation style as much as possible. So you'll rarely if ever get unanimous acclaim that a course guide is perfect, but done properly you could satisfy a large number of them perhaps.
What are some qualities you expect to see in a book or course guide that makes you think you're in good shape for the duration of the class?