This was several years ago and only once has a recruiter actually replied back with feedback shared by the interviewers. This was after they said, "sorry we found someone better". I reviewed the list and I saw nothing that would be considered "negative". I only found out later that the director was trying to hire their friend for the role.
Sorry if this wasn't helpful, but I guess the takeaway is that unless you completely bombed the interview, it's probably something going behind the scenes that was out of your hands.