Why are unit sizes still different between Gold titles?

[Volcano Man]

My memory is failing here, but wasn't the reduced Stalingrad units sizes due to the reduced strength at the time of the battle? The issue however is that in some titles the designer set the actual (average) battalion strength on paper to be the 100% max strength in the OOB, which means that they don't recover strength beyond that level, and their firepower is treated at full effectiveness rather than being reduced (when a unit gets below 70% strength).

But I can tell you the short answer here: because making a change like that would require reworking everything, including playtesting. If this was a serious issue then it would have been evolved through mods by now (and it never was). Maybe we will have a new wave of PzC Gold modders. ;)