I think the remedy to this is quite simple - read your history! In real life the conflict was fairly interestingly balanced, so balance with features that reflect the history must be possible. If you don't know how, look at the reasons evident in history and you'll get plenty of ideas about how to make the game situation at least as balanced as real history.
right.. so Ai, player, other players in MP will all act 100% as in reallity - the allies NOT mobilising for war till 1938/39 and beeing supriced that Hitler is not being true to his promisses ... right...
all actions that are not 100% historical would chance the "interesting balanced" outcome if you would travel back in tie... greatly! If the Allies would be suprised by the danger of war you might be right, but they are not...
so.. maybe make a mod with all the "historical colonys" but with all actions each Ai and player can do stricly scripted without possible chance.. wait.. it's a game... can't do this... you have to balnce it for the sake of the game... and they do it
EDIT: sorry, midread some points... nether the less.. all I wanted to say is that I am looking forward to see the balancing they are doing... not that it is not possible.. far from it...