At places like Princeton, most people become professors because they are good at research.

The issue today, IMHO, is that every university is looking for professors who are "good at research" (meaning, they can win grants), and teaching is not even a secondary or tertiary thought (if a thought at all). The last four professors we hired in our STEM department could barely speak English (I am in the states), let alone get points across or create examples. You know what they can do well? Write grants that get awarded.

Research and teaching are both important, and a smart university tries to use its professors' talents most effectively.

I studied at the VU, where Andy Tanenbaum, writer of a ton of famous CS books teaches. Of course I followed his classes. His books are excellent, but his classes are basically him reciting his books from memory. The jokes are literally identical.

At some point, more and more of his classes would be taught by Maarten van Steen instead; he's an excellent teacher who really knows how to engage the students and make them think about problems, instead of merely telling them the answer.

There was another professor who, as far as I know, didn't do any research at all; he just taught a ton of classes.

A professor who is great at one thing is not necessarily good at something else.

Research professors who have 0 interest in teaching and farm out the actual teaching/grading to grad students has been going on for decades.

Perhaps, we should have a conversation about whether professors are indeed even teachers.

>a grad class called "Hard problems in combinatorial optimization".

I don't think that that is an introductory course.