I played it with the 3rd Reich and the best thing would be to increase production cost of tanks. I had no need to produce infantry since for the same time (turns) I could build a panzer which is much more powerful. As i said this i the Scenario thread, a suggested speed would be 2-3 turns for infantry and 4-7 turns for armored units. A panzer II could be 4 turns while a Tiger 7 turns. This would make the infantry much more used since it takes considerable less time to build, and having tanks would be like a show of industial and militart power. Otherwise I was playing the game with heaps of tanks and no infantry since there was no need for it.