I'd love to hear more detail - the past podcasts were interesting but largely fluff.
Maybe post a thread on HN asking for volunteers who post a description of their startup and you do live office hours with the highest voted startup each week.
On the question of who it would be cool to hear from, I'd love to hear from YC alums talking about their YC experience, not just a sentence about it but going into detail about mistakes they made and things that helped.