I suppose this isn't "little," but it'd be nice to have a captain's cabin as an OW "menu."
As in, when the player is in OW and wants to "consult his maps/charts" or "check on the provisions and supplies," etc. etc., he can have an aesthetically pleasing cabin-themed menu with an immersive UI.
It would also be nice to visit one's cabin, consult maps/charts, chart a course, and then "order" it, so that the officers and ships crew go into a sort of "autopilot" mode, enabling the player to focus on other things (economy, equipment, studying maps, chatting with team, etc.) instead of micromanaging the excursion.
Of course if the ship comes under attack, the captain can be alerted and the "autopilot" disengaged. Perhaps the captain could also choose to be alerted when any particular type of ship is spotted. (For example, the captain of a privateer could toggle a preference to be alerted in his cabin when a Trader Brig or Trader Snow is spotted, but left alone in any other situation apart from direct combat).