I think that we need historically inspired gameplay. It doesnt have to be historically accurate, it just needs to be inspired by real life meta.
Weapon designers created the weapons based on the reality of the time.
In WW2 you needed a BIG gun to have a lot of penetration, armor worked.
In 1950s/60s MBTs were kings, not time traveling tin cans from 20 years in future.
By breaking these rules we create inconsistent, and IMO unfun gameplay. I dont think its good gameplay to try to make everything competitive at its own BR.
I don’t see many instances where these rules are actually broken in a meaningful way.
Ww2 eras still have armor that works. There are plently of strong heavy tanks with good armor (KV-1E, KV-1 ZiS-5, Tiger 1 and 2, Jumbo Sherman). And heavy gun vehicles serve their purpose of destroying the former rather easily.
In cold war eras, MBTs are still the most popular choice by far. Most games will only have a few players 1st spawn AA.