So, just like OTL USN prior to Pearl Harbor? The USN never really took carriers and subs seriously until the battleships were taken out at Pearl Harbor.
I imagine though without the obsessive need to focus on offense to make up for lack of ships because of WNT limitations, they have more pilots, reserves, and better damage control and logistics then? And more balanced designs for both ships and aircraft both. Logistics-wise at least, with better trade and relations with Britain and America, Japan should have more merchant ships available.
Hopefully this includes a more tactically-adept officer corps where the favored tactic isn't mass infantry charges ala the Western Front 1914.
Hopefully their fighters will be of modern, properly-designed and effective things along the lines of the Ki-61 Hien/Tony, or the Ki-84 Hayate/Frank, as opposed to the flying death trap that was the Ki-43 Hayabusa/Oscar.
Bomber-wise the IJAAF actually had a properly-designed medium bomber with the Ki-49 Donryu/Helen, though earlier models were slow and had a low bomb-load. Preferably they should have the Ki-67 Hiryuu/Peggy, which apparently was comparable to the Ju-88 in terms of performance and versatility. IJN ground-based aviation should use those planes as well, or naval variants thereof, instead of those G3M or G4M deathtraps.
The Japanese are still allies with the British, they probably received help in proper carrier design. And the Long Lance torpedoes were double-edged swords, given their instability. Shorter-ranged, world-standard torpedoes are fine enough on their own, at least they won't blow up the Japanese warships at the slightest mistake.
