"Having pre 1943 tanks fight BP (and the Archer in its currenty form) isn't going to work well"
Its an arcade game, it can and will work, for example kv1s being able to challenge panthers, kv2s being able to beat panthers and tigers in coh2. We have examples. It isn't like this is completely out of the nature of the game
(Also plz gib panzer 3 M, sexiest german tank :V)
Yes CoH is not realistic but it trys to feel authentic. That is why a big tank like the Tiger, IS2 or Churchill can take a few shots while something like a Puma or Su 76 or T34/76 goes down rather quickly (also there were always people that felt stuff like Tiger beating IS2, Kv1 being able to challange Panther, etc. felt out of place. Those people would feel the same with Panzer 3 being too strong)
If Panzer 3, a tank half the weight of Panther, would be able to fill the role of the Panther then that would feel not authentic.
And if Panzer 3 were really to be buffed to Panther or Panzer 4 levels then why not simply make it Panzer 3 vs Shermans or Panzer 3 vs 2pdr Churchill in the first place? Would be more historically accurate with the same outcome