Agree with you 100%. I took a poetry seminar with 12 students and two faculty members (from different disciplines). You couldn’t have achieved the same ends in a lecture hall- or even with 25 students.
But Crick and Watson- wow.
One of my kids still describes what happened when the professor (who had won a Nobel prize the day before) walked into the lecture hall. It was like Elton John and Paul McCartney decided to attend your music recital-- the students went absolutely nuts. Everyone was expecting a TA to announce “professor X sends apologies”-- and yet, here he is, a week before finals, ready to give the “summation lecture” to wrap up the semester.
So I respect these “fantastic scholars, amazing teachers”. Would be a pity to limit enrollment !!!