That is simply cherry picking stats to create a distorted impression.
The stock Comet/Churchill have 290/240 armor and then there are allot more high armor doctrinal tanks and commanders that have them available to allies than there to axis.
Stug/JP have 59% and 70% vs Comet/Churchill.
The FF has 81% chance to penetrate a Panther (highest Ostheer stock unit) max range and SU-85/M36 has 85%.
Vs a brumbar 88% and 92%.
The only stock unit with high armor is the OKW KT.
Increasing the penetration of JP/Stug might make the "way too OP" but it would bring them inline with allied TDs that are already "way too OP" that not only have higher penetration but they also get penetration bonus with veterancy.
Imo IS-2 armor (and other similar units) could easily have their Armor greatly reduced and move to veterancy bonus instead.
I get what your saying about allied td,s. But stock axis armour is jus way higher specificly the stock kt has twice the armour most allies can bring out stock. Allies need a doctrine to do the same. So allied td,s being way op have the kt being stock as a valid reason. Unless deflection or x% chance to do deflection damage is implemented.