We need more supply convoy's I.E. Trucks,trains, and boats, heck even aircraft.
Convoys of Merchantmen (2-12) or solo merchantmen.
It would also make port facilities extremely importnat and they would likely be far better defended as well in terms of shore batteries and AA.
But geez, think about divebombing ships in your Val, Stuka, SBD, or Kate. Torpedoing with aircraft, skip bombing in mediums, raiding in cruisers and PT Boats.
By the way, I think a nice American light cruiser like the Brooklyn Class would be a swell addition to the game for it's AA siute and close in fire support capabilities as well as a lovely add for raiding convoys and ports.
Boise is below.