I might be mistaken, but it seems like the only person who can create player journal entries at the moment is the GM. I'd really like the option for the players to be able to create their own entries and share them.
I run a game which is largely based on self-reference, and part of the system is players in a scene taking notes of events and using them to introduce later twists or explain previously unexplained events. It'd be great if we could do that within the current player journal system, especially with the possibility for sharing entries, and highlighting notable parts.
Additionally, the ability for players to create journal entries would be great for blue-booking or epistolary games, or other sorts of things based on that sort of first-person narrative.