More Factories like plane factories, veichle factories, ball bearing factories, and even railroad depots. All these can play a factor in the war. The Plane factory could increase the Perk Point cost and the same with the viechle factory also when they are down. The ball bearing would limit the amount of punishment the engine could take, the overheating. Raildepots would limit the train supplies to the rest of the factories.
With the factories now they dont change anything. Maybe cause a few radar problems or AAA problems but thats it. Why even have factories if they dont have any effect on gameplay.
For WWII Online when there factories go down the whole country would feel it and pay the price for leaving their factories unprotected.