I've had different experiences, 2 SU-85s at range can do tonnes of damage to a buttoned panther, panther dies and SU-85s take no damage since if the panther is buttoned it can't shoot back. Maybe you just went too close to the panther with the SU-85?
Also it is expensive to tech up to panther while producing units to hold the map in 1v1. Panther should be good at what it does. Button, ram, AT nades, IS-2s, AT guns and SU-85s, there are plenty of soviet combined arms usage that can take out panthers.
I never understood this line of argument in VCOH either. The Axis player need only make one non-doctrinal unit, then is able to focus on it alone for the match up you describe, and has all the mental RAM he needs to micro effectively. The Soviet player needs to max out a doctrine (eliminating the choice for all soviet players in 3v3 and 4v4 matches as all axis players spam Panthers) then spend more resources to make an IS2 than the Panther costs. And the panther has better range, better penetration. Then the soviet player needs to buy additional AT and Su-85s or T-34s and manage those for the encounter as well as his AT nade infantry. Who the fuck would choose the Soviet option given the circumstances of the choice? Make one practically unstoppable unit provided you have decent micro skills or dedicate half of your army to fighting that one unit? I've switched to Axis til they patch this mess and just spam Panthers as well now. It's hilarious, you'll vet them in no time.