As for fixing 4's, i dont think there is a good solution for it. You would need to change the armies, the balancing process and a couple of game mechanics completely...
...Thats why i dont see the point in brainstorming ideas for 4v4's. You need to change the game completely and that wont happen.
Nonsense. Just give the Americans bazookas with as much anti-armour punch as panzershreks, and that right there would close about 90% of the gap with the Germans for that faction. As for the Soviets, allow their AT guns to penetrate the frontal armour of a panther at least moderately, and/or buff their PTRS rifles so they're not utterly useless against anything more powerful than a scout car, and you've once again gone a long way to balancing the situation out.
The fact is, right now, between Sturmpios and Ubersoldaten as infantry, and PIVs and Panthers (never mind the even more powerful tanks the Germans get!), it's like the Germans are running around with guys in superman capes and frigging impenetrable M1 Abrams battle tanks, and the Soviets and Americans are equipped with slingshots, useless bazookas (Americans) and utterly useless PTRS rifles that can't even really hurt a PIV, never mind a Panther, Tiger, King Tiger, Jagdpanther, Elephant, etc. etc. I'm saying give the allies a gun of some kind, even an old revolver for crying out loud, rather than a knife at a gun fight.