Most USF tanks get penned frontally by a panther no problem. Why is it an issue when a end game tank destroyer can effectively engage and kill axis tanks? Even then, good micro is required in the USF side when fighting even higher armored tanks like Tiger II. If Jackson needs to be toned down, so too does axis armor. Both have seen power creep to this point. Normally I like your balance suggestions but Jackson being doctrinal and making USF have to use m10s to fight axis armor is laughable man.
You are only reading the nerf and not the counter buff.
But to start off, the panther, while more expensive, also has 10 less range meaning to engage its closer to the line, more apt to get hit by at guns and close to snares. It's also not great at chasing. Additionally when it takes damage it needs a unit to come and fix it and finally ALL factions its faces have access to a unit that out ranges it.
I argued that allied TDs need a buff when they were unreliable, including the Jackson when it dealt 240 damage but would often bounce a p4 and am now arguing that they need toned down as they have made the armour system irrelevant.
No unit in any faction desires to break the basics of the game. And as lonb as it remains broken no sherman AT variant will be worth anything. Why pick a tank that has an increased chance to pen the enemy while in range of return fire when you can get a unit that out ranges the enemy and is nearly guaranteed to pen no matter the target?
And the fact that you are using a panther, a more expensive and shorter ranged unit to compare to instead of the 3 other 60 range TDs within the same price range says all it needs to.
Keep in mind that the swap would include adding deflection damage. Say it does 80 damage of deflection, a pair would be about as good as a current Jackson, but more involved and more counter play (as well as making it less all or nothing)
The goal is making armour reliable to counter but also reliable to use. Instead of effectively being a y/n equation using the proper tools would be a y/Y! equation.
Basicly you would, while using an m10/jackson/AT sherman (via HVAP?) always be doing some damage to big cats, not necessarily full damage, but every hit is something they would have to repair. No more diving against dedicated counters and having RNG say that 18 AT weapons are going to deal no damage at all
But at any rate I've said my bit, I'd be happy to further the discussion in a dedicated thread, but this one is about the E8