Are you considering adding special shell ammo types? Such as Semi-Armor piercing (SAP), Base fused HE shells, Common shells, special common shells, and Diving shells? I think adding these would give the designer that last little bit of customization it needs.
Also, I think adding a aiming point selector for battle would be nice, let me explain,
In the game Silent hunter, you were able to tell the gunners of your ship to aim for certain points/areas of a ship, I.E Aim for the water line, or aim for bridge, or aim for the weapons, etc I think adding this in would greatly benefit combat, as it would make so that smaller guns won't just be trying to uselessly hose down a BBs belt armor but instead can be told to aim for less armored superstructure of a ship