I always wanted to create partisans, and suplies.
one thing that I might think might balance the game would be this rule;
china; china collects income for EVERY chinese terr without a japanese unit, and the can build infantery in any chinese terretory without a japanse unit. however. max 1 unit per japanese held terr.
or one could have; china collects full for every chinese occupied terr, and HALF for every empty japanese occupied terr.
these rules makes some historic sense, the japanes neede more forces in china to deal with the civilian population in the occupied terretories than they needed to deal with the chinese army.
also, I would LOVE partisans and supplies. 2 rules for this; soviet union can build partisans in german occupied terretories, they cost 1 and are 1-0-5-0 units. every 2 units = one combatdie on defence. after place new build there is a special partisan revolt phase in which new partisans gets to attack (for 1 round of combat) in all the terretories with partisans in.
if you cannot trace supplies to your capitol, your panzers become 2-2-1 and arts no longer help infantry. you can chose your order of combat to gain supplies to another combat. (ex you can attack east poland form west poland, so that the units in belo that attacks east gets supplies for their attack, if the combat in poland are successfull.