In short and I expect this has been done to death:
If the Tiger had as good a view as the M4 through the gun sight its superior armour would justify some perk in terms of surviveability to for example air atack.
As it is the M4 is a better alround tank as in equal or better gun and much better view form the gun sight.
Im my humble opinion perk both Tiger and Firefly for their rareity but give Tiger same view as Firefly.
Eventally bring on standard sherman with same values as T34 with Mid war availability and an ability to destroy both Pazer and T34 and Tiger from behind.
Ideally get an unperked British Cromwell as well.
