As a story admin, I can see contributor drafts at the conclusion of each chapter, but it would be very cool to be able to see all unpublished drafts for the story in the map (possibly with the ability to toggle drafts on and off?)
I think that was once possible and I'm not sure why it doesn't exist (anymore.) I could imagine that inexperienced story owners might delete other users' drafts by accident, so it might be useful to have additional notice when they try to delete such chapters. (Though there was also a bug in Firefox that prohibited the site to properly show the labels on the story map, so these chapters didn't appear as drafts in the first place.)