The only thing i remember from pershing doc in tournaments is caster joking that someone remembered to use combined arms.
People don't use it because it has a reputation for being broken, and not stacking with veterancy bonusses. However, that was (stealth) fixed by Mr.Smith a few patches ago. It's a remarkably strong ability right now.
Its durability didnt go up, it was exchange of armor for HP. Better in some cases worse in other. Not a buff but adjustement.
I think more hitpoints in exchange for some armor is definitely a buff.
With the way armor and penetration works in this game, armor is not very reliable at all, and especially not the "medium-heavy" category of the 300s. The average anti-tank gun can penetrate (~66% chance) 5 times in a row or it can bounce 5 times in a row. There is so much RNG involved, it's almost impossible to make a sensible estimation on a situation.
Health however, is much more reliable. You know exactly in how many penetrating shots it can go down, that's a fact, there's no RNG that can change that. Now you know most shots will penetrate, but you know exactly how many the tank can take. This means it's much easier to judge chances and risks. The armor for health change was done for the Panthers about a year ago and it has made them much better to play both with and against, because there is now less RNG involved and it has made it generally much easier for either side to judge whether a push or a chase is worth it.
I would personally definitely count this as a net survivability buff. Especially for team games, where AT is usually concentrated and in abundance, and in which a higher health pool is a lot more useful.
I tried the mode against AI. The one shot wipes are gone (which is good). Its a nerf to pershing.
I don't think it's a nerf at all. It still (on average) kills clumped up squads in 2 shots. The rare oneshots are gone, but now it will hit more often and deal more damage against squads in the open.