I'm no expert about how real CV's were built and attacked, so please bear with me. This may come out overly gamey anyways, but it seems to solve the provlem of kamakazi jabos. Did WW2 CV's have armored flight decks?
Anyways, change the way damage affects a CV. Introduce AP bombs for the divebombers, and probably the TBM.
GP bombs would do half damage to a CV, requiring 16000lb's.
AP Bombs would do double damage, meaning four SBD's could kill a CV.
Torpedos would also do double damage, requiring only two torpedo hits.
This makes defending a carrier, as well as realisticly attacking it somewhat more likely. The divebombers and torpedo bombers are fairly easily dealt with by fighters flying CAP, lacking the speed to just blaze through any CAP.
As for airfields, I've never reallly seen suicide jabos, besides the occasional(okay common) p38 that compresses and digs a hole in the ground. That said, base capture is too easy, and its too easy for jabos to kill targets at a field and get out alive. All it takes to capture a field is a coordinated flight of p38s, 1 per hangar.
What I'd like to see is ack moved into 2-5 "banks" (depending on the field size) Each bank would be a dense pack of ack, dense enough that a bomber could carpetbomb an entire bank at once, or a jabo flinging bombs/rockets at it could take a good chunk out.
Ack lethality would be turned UP so that instead of "BS" one ping ack kills, just about every hit from the ack is a one ping kill. This requires the ack to be killed before a decent attack can even begin, and also helps eliminate lamers suiciding through the ack in hopes of shooting someone trying to takeoff/land.
Then again, there isnt much thought put into these ideas, just brainstorming, so there may be major flaws.