JMJT
My idea is to remove entirely those discussions deleted by those users with the Faculty role. Many faculty members at our school have requested that, once they delete a discussion, the discussion be entirely removed. "When I delete something like a discussion board, I would like it to be entirely removed -- I do not need to continually see it as deleted. This clutters my view."
I understand, and agree with, the reasons for Populi to keep the deleted discussions. However, keep the deleted discussions visible for only those roles higher than the Faculty role.