Hi John, it's not really the gun caliber like on a Firefly or a tank destroyer, but armor thickness. I'm with you on giving the amount of particular hits on a tank vs actual history, but it's Tamiya's design and only until they (or we) can change it to make it closer to historical accurate then it is stuck that way.

I mean, what Sherman would really take one hit from a Tiger and survive? And if you do place an American tank destroyer on the battlefield, then due to it's light armor in the turret it would have to be a light tank.

The Firefly and the standard Shermans must be mediums, just to be closer to being fair against German heavies. The uparmored Jumbo due to weight and armor thickness would be a heavy.

HTH