Panthers always have 960hp iirc. It even used to have 320 front armour and 0.065 move accuracy!
Reading through old patch notes.
60td were originally set as cheaper mass-able with explosive damages at rng range
Today 60td are now less explosive but constant damages at virtually no rng. While costs gone up, but still higher efficiency as compared to their opponents, with crazy vet bonus.
Imo the equation of safety range goes well with rng and explosives.
A -5 range change makes most sense now they are dealing constant hp bleed, the need for distance margin should be lowered.
55td is still higher range! 55td still have clear sight/accuracy advantages! 60td should be reserved for slow ass ATg and callin Td. There are not much changes required down line for armor imo
And yes jackson went from mass AT tanks to highly efficient AT brawler.
Panther has gone through multiple versions. If we talk about release, it was basically a T3485 with more HP. Then it went to be for years a tank hunter (armor + pen) with 800 HP which gain that 960HP back through vet and been expensive as heck.
The current version basically rollback the armor in favour of giving it back the 960HP back limiting it's armor value. This means that it can reliable engage enemy vehicles without relying on a flipcoin on whether a hit would pen or not. Pen has gone up and RoF was buffed.
Not sure what you refer to "explosive damage".
Su85 were tailored towards been anti medium tanks. The vehicle became "obsolete" once OKW was released. It was easier for OKW to put out heavier armored vehicles compared to OH (PV was strong but almost impossible to afford en masse). This was also paired with Su76 changes, which were enough to counter medium tank and heavier (due to sheer amount of firepower) and just spam barrage with them.
Penetration went up and RoF was nerfed instead. They never had issues with PIVs before at 4s RoF and been cheaper. If anything, cost wise, it's way more effective dealing with TDs now than before.
Jackson had 480 HP but their cannon had lower pen with BIG 240dmg value. This was barely fine on 1v1, when volume of units is lower, but made the faction basically useless for teamgames outside of early to mid game. If you couldn't end the game before 20 mins, you would basically stop trying.
This was the preview patch on which Jackson at 55 range was tested and discarded