Admitedly, PIATs should be reversed to what they were just before 0.0.4, their AT capability is just a bit too great right now.
003 Piat effectiveness was basically useless for most cases. I'd recommend keeping the existing changes, but bump the muni price from 85 to 100-110 per piat upgrade.
A STuG will not kill an infantry blob, and if the blob is smart it won't be kited. PIATs are insane right now and skirts hardly affect them.
Stug won't handle an infantry blob, StuH can though. Axis has a much easier time of kiting than allies. All manpack AT has 0.35 accuracy at range. But bazooka has poor penetration and big scatter, PIAT is very accurate at hitting where the tank was at, but is not homing (the direct fire manpack ATs are homing if a hit is calculated) and RRs hit often but have low damage.
You can kite panzershrecks (low scatter, high damage) with allied tanks effectively with a spotter, which lets the tank outrange the AT inf. Without a spotter you still can, but there's a chance the AT will hit. An axis tank with a spotter can similarly outrange allied AT inf. Without spotter there's a risk of getting hit, but bazooka has poorer hit chance and PIATs will hit where the tank was, not where it is (unless you drive towards the PIATs, in which case it deserves to die anyway). So as long as you keep moving you are safe.
What screws axis tanks up against these AT weapons are:
[1] Giving side or rear shots, where the 1.2 / 1.6 damage modifier does massive damage in a short space of time. I do think these modifiers should be reduced, but relic made a lot of tanks have them.
[2] PIAT being able to fire over obstacles, which makes fighting them in tight areas with obstructions very tricky.
[3] Bren buttoning slows axis tanks down. Most people haven't got the knack of kiting down, very few do. At max range you can shake off the button easily, and anyways there should be some backup behind the tank to provide anti-inf cover. Anyways there's a button change coming up in the retail patch, the fewer men in bren squad, the smaller the speed penalty of button, so you just need to start killing some men off to get enough speed to get away.