It would be nice to see Japanese tanks in the game. Unfortunately the Japanese didn't cooperate back in WW-ll and their armor was bloody awful.
They had some sound armor tacticians in the IJA, a few that studied with the Germans. But unfortunately a lot of this expertise didn't didn't dribble down to company level. So the actual use of what lousy armor they had was mostly unimaginative and poorly executed. The mind set of many IJA officers was that the tank was un-manly and not in tune with the warrior ethos.
They were really in no position to start a war against an alliance of nations like Australia, Britain, and America. The lack of effective armor and doctrine was a big reason why.
In The Battle of Khalkhyn Gol they got a birds eye seat to modern armor tactics/combined arms as executed by one of the greatest tank Generals in history, G. Zhukov. Unfortunately for them I dont think they actually came away from that battle with anything other then a defeat. For the most part modern tank design and manufacture took a back seat in Japanese manufacture and IJA doctrine.
Its a good thing for us they didnt have type-4s in '42, or even '43.