I'm not saying they should just limit it to France and Prussia but keep it simple as far as what factions they're doing. They should all be similar enough to maintain balance and to keep it from getting weird. Like in the earlier versions it was just weird to see Russians, Japanese, Italians, and Dutch all fighting the Prussians while Belgian artillery goes bonkers with a krupp gun. And yes, the 20th Century Factions were a game breaker.