Been asked before, I know. I'd like to see the the addition of player controlled ships to function much like the GV game. Players can spawn ships out of ports just like GV'ers come out of V-bases. Spawn points can lead to other ports or to an area in the middle of the high seas "shipping lanes". Controlling this point can allow access to other ports. We've already got the cruiser, destroyers, PT boats modeled in the game, but we could also use cargo/merchant ships to function similar to M3s. If the merchant ship gets close enough to a friendly ship, they can resupply/repair the ship. Also, these merchant ships can resupply ports and reduce downtime by an amount greater than lvts/m3s/goons as it is a big, slow target in the open. These player controlled ships can assist with base captures by shelling fields or defending a CV group from the enemy, but have no means of launching troops or aircraft. These can only be spawned from ports, I don't think they should be able to spawn directly from CV groups although they may potentially reinforce a CV group as the waters are open for travel.
That's the gist of it, not going to get too technical right away.