Your first mistake is compare to the panther to the su85. its retarded logic so dont do that again as both units are fundamentally different . can a su-85 handle 2 p4's when properly used? yes. its impossible for the p4 to win from the su85 from the front that's why skill and a good army composition is a great factor to prevent any tank from flanking the su85 and force them into the su85 firing arch. i dont deal in 1 vs 1 scenario's because that is retarded.
continuing on.
Now the panther is a front line slugger. and as slugger is the most inefficient unit in the game it only has 800 hp better armor but very poor dps allowing soviet generalist tanks to cost effectively engage it. for the record the shermans and t-34-85 rof is significantly higher and they have the penetration to knock the tank destroyer out.
and i dont consider specialist tanks worth if they cannot deal with at least twice the amount of fuel and mp in generalist tanks. increasing its ROF 4.5 seconds will fix most of its problems
thats the problem here. u are using it like a front line slugger. that is not proper usage, its a tank, you expose it to the least amount of enemy fire and try to do as much damage as you can, by flanking and using shot blockers. you run away when soviets are supporting their tank better than you, not sit there and take shots just because its a panther.
1v1 is the scenario where it justifies the panther's unit cost(NOT TECHING COST), the panther reigns supreme, no other tank bar the is2 can brawl with it. how many t34 or shermans are you want it to face off? not even a single tiger has a chance with a swarm of t34.
dealing with twice its cost is a matter of usage. a sniper is a specialist unit, can it deal with 3 gren squads? the sniper has no chance if 3 gren squads were to bum rush it. but a sniper at range and with a screening force can put the pain on as many gren squads as you can throw at them.
what you are asking for is a OPed tank, seen back in the past versions of the game. stupidly quick with blitzkrieg, stupidly tanky due to soviet pathetic gun penetration and its huge hp pool and with a escape mechanism. you have played with it too long and are far too comfortable with it. its time to adapt towards a more balanced game.
stats wise, the panther is fine. its tough, its tanky BUT its prohibitively expensive. not the unit cost, but the teching cost. its much cheaper to wait for cps for a tiger tank than tech to t4 and buy a panther. thats not the fault of soviets tanks getting buffs, those buffs were long overdue.