Back to the problem in game with CVs... let's look at the attack at Pearl Harbor.
As the Japanese I attack Pearl Harbor twice with air attacks and sink a paltry 2 BBs. Having expended my OPs, the CV group is unable to move. I then switch to the US, sortie my surface task force and attack the Japanese and sink 1 CV.
So it doesn't make any sense to attack Pearl Harbor. The day that will live in infamy.
In general I think naval units have too few OPs. Hell, once you get into 1943 the American fleet is always at sea... it never returns to port and is replenished at sea. I think that needs to be reflected in the game.
My recommendation would be to increase OPs for naval units to 3 OPs. If nothing else, this allows Pearl Harbor as one can attack twice and then move out of the area.
I would also recommend that expending a Supply Oiler, not only replenish fuel, but also OPs as well.
A fleet at sea is supported by Cargo, Ammunition and Tanker ships. It just doesn't make any sense for major fleets to have to return to Port if the player doesn't want. As the only support ship that is represented in the game is the Supply Oiler, more importance (just like trucks) needs to be placed on this unit.
CV vs CV battles really need to be adjusted. You just don't get to have a CV group conduct 2 (or 3 if changed) free attacks without a response, as I have discussed before. It is just not the way CV fights worked.
When a CV group attacks another; you should have an attack phase, followed by a counter-attack phase and it shouldn't matter how many OPs the enemy CV group has. So if I want to attack the enemy CV group 2 or 3 times, they should receive a corresponding amount of counter-attacks. After the turn ends, if battle is continued, once again the enemy CV attack should be responded to by a counter-attack. In a full fledged CV vs CV battle, one side will gain the upper hand due to the amount of aircraft lost. CVs will be lost on both sides, not just one.
Overall, I think the game needs to take a new look at the way they handle fleets and especially carrier warfare.
I know that my proposed changes would cause a major revision of the game. But, IMO, if the naval portion of the game is flawed... you will lose a lot of sales by those who want to relive the amazing naval conflict which was so characteristic of the War against Japan. And that impact will also be felt in WarPlan 2.