I completly agree with you analysis.
The sole benefit of refuling would be that USA is forced to attack Japans Islands BEFORE taking down Japan directly.
But experienced US players never go after Japan anyway.
And your suggestion will make it even worse. First you got to get a navy capable of surviving, THEN you have to start taking islands.
Besides, it will feel very strange if you cannot move from england to egypt with a ship (if you are unlucky with how things goes etc) cuz you got to go back to england and refule.
But if you implement a port which can be a safe place for your navy,
thats a small start to make islands more important. If you in addition
allow a player to place max 1 ship and 1 infanteri (marine)
on a navel base, that would further improve the importance of these islands.
Damaged 'battleships' needs to go to a port or navel base is an further improvement. This we seem to agree upon. If japan dominates the seas, this rule may give US enough time to maybe attack and take an island.
Maybe also add a rule that if a ship is in port, and that area is invaded by land units, then you take over all or some of the ships laying there. (maybe at 4+? per ship).
Last thing, and this I find very important, even if you do not have an supperior navy, you should be able to use it. It should not be just dead meat.
Lets say US sends two full transports and one destroyer to escort her. Then japans attacks with 2 battlships and two fighters. One of the transports manage to escape from combat while the destroyer and other transport must fight. They are both destroied, but the destroyer manages to damage one of Japans battleship forcing it to retreat to a port next turn.
The following turn, US may with the surviving transporter take over one of the island, for a nice naval base, enabeling you to place infanteri and a transport, submarines or whatever there in the future.
In short, if you allow some ships in an sea zone to escape combat, you will
be able to be a threat for a far less cost. And be a threat much faster!
As long as the given Island is in the hands of US, it will be of a constant threat for Japan. Japan have to constantly blockade the port, (force partion of the navy to be stationed there constantly), retake the island, or accept that some of the islands nearby with high income will fall in the hands of the enemy.
I know that the pesky english transport outside Australia can be irritating for Japan, and as Japan I do want that transporter destroied. As the rules are today, I can easily do that.