The changes tone down repair speeds of the other factions closer to ost and soviet levels, which is a good thing in my book. There are also no changes to soviet repairs, so there does not seem to be a bias 
Oh I'm not suggesting any bias. I'm just noting that repair speeds are another disparity that skews how viable (either variant of) the Panther can be, and it may not be taken into account.
To my knowledge the panther has the highest armour value of any non-doctrinal tank in the game. It is by no means reliant on attaining vet 2 to "do things", if it wasn't doing things it's hard to imagine it would ever hit vet2
. If the game files in the mod tools are not severely outdated it has even 20 more armour than a tiger and at 800 hp the highest amount of health of any non-doctrinal tank as well. (please keep in mind that it might be that the game files in the mod tools are outdated, personally I didn't expect the panther to have more health than any other medium tank)
Defensively speaking, the panther is fine. It's just unreliable as anything other than a damage sponge. And with the increased armor with vet armor that role was further solidified. That's all I mean. Vet 2 panthers had that much better chance to bounce key shots so that they could stay in the fight long enough to get another round or two off. (Which would likely miss.

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The Tiger, incidentally is another unit that's suffered on Ostheer's roster due to WFA and UKF.