It's not about fixing anyting. It's about late game AT options.
Units with pen 200 or higher:
Wehrmacht: Pak40, Pak43 Stug G, Tiger, Panther, Elephant.
OKW: Raketen, Pak43, JP IV, Panther, Command Panther, Sturmtiger, King Tiger, Jadgtiger.
SU: ZiS-3, SU-76, SU-85, KV-2, IS-2, ISU-152.
USF: Jackson
Pershing would add more deep to USF. More late-game options cause currently it's just Jackson spam.
Also, why USF is the only faction with 1 unit which has 200+ pen? It's not good design when only 1 unit has good penetration.
For the people saying that we will see Pershing every single game - you said same thing about E8 yet after first week since release when there hype for E8 was gone, Infantry and Airborne went back as a better choices.