Strategies to win with the Allies: Kill Germany First (KGF).
Bomb the Germans with USA, UK invasion force (with some USA support)
Russia holds, expands as western allies open new front.
Japan can help Germany hold on by back door pressure on Africa (take UK money) Japanese ftrs landing in Europe to help defend key territories.
Summarizing… if playing to win, games will go mostly along these lines. Of course, the allies can always TRY to get cute and go after Japan, but that is VERY HARD, especially against a good Jap player, mainly because there is no true monetary reward for USA when confronting the IJN.