I think there are 2 easy changes that would make naval combat feel more fulfilling without a complete overhaulPerhaps they can do a Japan/US Pacific update. Fix the naval situation as well making it more dynamic. Naval Battles in HOI4 feel really shallow and most people don't even use navy or just spam naval bombers.
I have been playing Axis and Allies Anniversary edition and second edition with friends. Navy is a big part of that game and the Pacific War feels somewhat real in it. Of course A&A is missing it on the ground war without logistics and production that is seen in HOI4 and I would say HOI4 is overall a better simulator but it just is lacking from a naval point of view.
I am not sure how they fix it other than having you move fleets more like in EU4 or Vic2 but that would create a lot of micro-managing.
1) Non-combat missions. Things like shore bombardment. Basically give fleets something to do other than just sink other fleets and sit next to naval invasions. That makes knowing where the enemy fleet is significantly more important, and means large battles can happen aside from joining patrol battles (Midway and Guadalcanal come to mind straight off the bat)
2) A battle log. Give us a text log of the calculations so we can better see how the battle is progressing. That gives the battles more flavor than just watching the bars go down two or three times a day. Which in turn makes them feel a little less shallow
In that regard, ship captains would similarly provide a layer of attachment to each ship that would help provide more depth
There is a 3) of knocking NAV and TAC out of the naval meta, but it looks like the air rework coming with BBA might have that handled