Thought I'd pop up my wishlist now that I've actually been flying again:
1) Ki-43 - The main fighter of the IJAAF for the duration of the war, and its absence is pretty glaring. Last I looked at this, you could get maybe half a dozen new planes with the Ki-43-I, -II and -III just by using different gun options in the hangar.
2) The Japanese plane set in general needs some love: A5M, Ki-27, Ki-44, Ki-45, J2M, D4Y, B6N, Ki-100, N1K1-J. The Ki-61 and I THINK the Ki-84 (been a while, but IIRC, the Frank occupies an area somewhere halfway between the AHI and II model standards) both are in need of a remodels, and like the Ki-43 you can get quite a few aircraft out of them with armament options in the hangar.
3) A loadout option in the hangar available only at land bases to turn the F4U-1A and 1D into the Goodyear FG-1A and 1D. This option would remove all the equipment needed for carrier operations (and more importantly, the associated weight).
4) Remodel of the F4Fs, including the addition of a separate F4F-3 model. The four-gun package on the F4F-4 only turns her into an FM-1. The F4F-3 had larger fuel tanks, but was still a fair bit lighter since she didn't have the heavy wing-folding mechanisms. The -3 was more popular among pilots than the -4 because as a result of having less weight she was faster, climbed better and was more maneuverable, while also having longer range due to the increased fuel load. The -3 was also the main variant fielded by Marine squadrons in the Solomons, so saw a LOT of combat.
5) Tiny Tims!
6) An ordinance option for AP shells for the B-25H's cannon. Research done after the B-25s were added turned up that the H actually often carried a small number of AP shells.
7) B-25J, with both glass-nosed bomber and solid-nosed gunship (12 forward-firing .50cal!) variants.