Technically, that’s good game play by America as that’s what America did in the real war. Can’t really blame them too much there.
Have you considered just making Japan monstrous while America’s over there screwing up Italian pizza and putting marinara sauce on spaghetti and making the Italian chefs go into apoplectic shock at the horror of what was happening to their cuisine?
W/o the US, and with Australia all ground forces, India and China should be down, the NOs for Hawaii and the Philippines should be gone at best as well as the ANZAC NOs and you should have the DEI and Caluttan NOs for Japan. Pushing into the Middle east is only wise if you ask me. Africa, I don’t know. The Allies are already there, I don’t think you could establish much of a beachhead in Africa, unless you are referring to Madagascar and S. Africa which might be good. (At least S. Africa to take a British NO and stop reinforcements down there, what’s it cost, 1 infantry and 2 rounds for a transport?)
I guess the trick then would be turtle for Europe and mass invasions on Australia at that point. An 80-90 IPC nation has GOT to be able to take out a 10 IPC piece of real-estate in the South Pacific.