What about creating stories that expire after 24h (like instagram/whatsapp)?
(Location) stickers on stories would be something funny too.
It would be cool if I can choose to allow/block others from screenshotting my stories. It's actually possible to block screenshots on Android&Windows 10. iOS can recognize it and send reports to the uploader.
Also, permanent deletion would be nice, so when I decide to delete a story, or when it expires after 24h, it's permanently removed from openbook servers, and not just "invisible" for us.