What functionality is missing? What is unsatisfying with the current situation?

When you click on "GM Screen" in the top toolbar, you have the option to prepare a session. This, to me, implies a space where I can make notes about the upcoming session. It does some of these things, like NPC data, but the main page that comes up seems to be merely a text field to fill out to the players prior to the session.   The same page could be a bit more intuitive (imo) by having a list of all the sessions handy, so I can plan ahead and move back and forth between sessions more easily.