OK, so the recent update messed this up completely on the other side. This is frustrating having worked so much twice (!)
I am not sure whether it is the "dogfight expert" thing implemented to address the tier imbalance, however now jap fighters have only minor chance even against a lower tier US squad (at least until TIER 6) due to the changes made.
BEFORE: Yes, US players may had a disadvantage early (like in history) but that is compensated later with the new planes and carriers.
Also I do not think that more squads for JAPs was/is a real advantage as the bigger squad size for US planes also makes scoring a lot easier - particularly multiple hits on one salvo (given the density of the torps and bombs)
I believe lower tier CVs should rather have more upgrade options for planes (also that later experimental planes should be omitted for higher tiers). With this numbers and HP would rather matter than the plane quality.
A quotation from WIKI... on IJN Zuiho: "Her aircraft complement consisted of six Mitsubishi A5M "Claude" and six Mitsubishi A6M2 "Zero" fighters, and twelve Nakajima B5N2 "Kate" torpedo bombers."
Having said all that my last suggestion is that 1 squad should be totally customizable for the player (FF/TB/DB) hence for a Zuiho a player should be able to choose +1 fighter as well. Not just the 3TB-2DB and the 1FF-2TB-2DB setups.
It is basically ridiculous that no fighter support can be sent with the bombers if CAP is also to be maintained.
In general this suggestion applies to all carriers.
Rgds
SAetta