I think this is an excellent idea--flexibility and diversity
are probably key to both traditional formats ("lecture" and "seminar").
For myself, I try to incorporate small group learning experiences
in my lecture courses, and I'm sure I go off on lecture-like
monologues at times in my seminars. Sometimes I think the primary
difference is really class size, which limits students' feelings
of accountability (as Dewey noted), and also inhibits their
willingness to speak up if they have a question or comment.
Robin