check those superior health and pen values again even ur stats disagree with u, axis get a bit more armor (not even always ex.panther vs comet) while allies gets more pen generally to off set, the health is almost always the same (640) with some outliners in all factions
and u forgot the stug
Stugs closest counterpart would be the su76, which supports your point about axis= durable and allies=pen since the stug has an extra hit of health and double the armour.