Thanks for the answers 
@Stuglife when something like this is mentioned I'd assume it is at least something that happened in the last year. So looking at the previous page still would not have given me the explanation I needed.
Also, The nerfs of the armor I believe did not go without reason. Won't we end up in a similar situation where we have to reduce the armor further (and then maybe in the future reduce the pen even more) and end up going in circles.
Some context of the last 5 yrs:
A SU-85 went from pen values of 200.0/190.0/180.0 to 240/230/220 in a similar time frame.
A Jackson went from pen values of 240.0/220.0/200.0, 480hp to 260/240/220 and +160hp.
I don't have data for firefly pen values in 2015. Live is 260/240/210 but hits for 200dmg
The real crux of the problem imho was Panther 320 armor, which on paper presented a formidable obstacle to deal with for AT guns and even TDs. After 320->260 armor in exchange for 160hp more and TD pen going up, Panthers almost became target practice outside of heavy urban or 1v1 armor duels. Combined with the very large pen increases listed above, the survivability rework led to almost every TD shot penning and bounces being very rare.
TDs have kept the same pen next patch, and a minor nerf to the
veterancy pen increase has not affected the base matchup at all. Vet II vs Vet II, TDs still have higher pen gain than the vet II panther armor increase.