Simulating a complete fleet is hard. Unless you make the player a fleet commander, but then, your game turns into a tactical one. If you're trying to stay within the simulation genre, you better…
…have an excellent AI controlling the ships accompanying the player.
Advanced Destroyer Simulator avoids this issue altogether and it creates an almost paradoxical historical situation in the process. The player takes control over a British destroyer in the 2nd World War. A lone destroyer, regularly facing off against enemy forces in superior numbers. What may be somehow imaginable in the Mediterranean (where the British faced the powerful Italian fleet) becomes almost absurd in the English Channel or the North Sea (where the British had the clear superiority at least above the surface).
…have a plan how to give the player still an interesting role in the missions.
Blood and thunder rule the country: The vicious Death Adder inflicts war on the kingdom and kills people by the dozen. Amongst the numerous victims are the relatives of three great heroes, who finally, when even their best friend gets slain right in front of their eyes, swear revenge.
So much for the usual excuse to have player controlled muscleheads beat up some baddies. But all of this is not communicated overly well in the actual game, is it?