I'd rather have a British fleet carrier such as the Indomitable or Formidable. The Essex class had less armor on the flight deck but the British carriers carried less aircraft, the latter doesn't realy matter in a game such as AH. I'd also like to see a Japanese I-400 class sub (the largest subs of WW2) with 3 floatplane/bombers onboard.
The Pacific submarine war is usually sadly neglected, American submarines were credited with 63% of all Japanese shipping losses.