I'd be very interested to see a sort of combination of these approaches, wherein questions are submitted in advance and upvoted/downvoted to determine priority,

I'd be very interested to see a sort of combination of these approaches, wherein questions are submitted in advance and upvoted/downvoted to determine priority, then the top x questions are asked and the answers discussed by a live interviewer. This would eliminate some (not all) of the problems that @pdovy points out while keeping the positive aspects of a crowd-curated set of questions.