Hi Derek Bell -
you are right - with the move to MOS we lost the Ideas Exchange and we are currently monitoring Topliners as we always have for informal feedback. We are investigating options to get a more formal way to gather ideas in the meantime.
Also, before the move to MOS, we (the PM team) exported all ideas from the Ideas Exchange and are maintaining them in our internal backlog management tool. unfortunately you don't have access to them there, but I wanted to assure you that those many years of ideas and valuable feedback is not lost to us.