Increasing ROF would mean nothing if the shots keep bouncing off. No, USF players are pissed because they don't have Pershing tank while all other factions have a heavy tank, so we have to rely on Jacksons as only viable way to counter heavies.
The Pershing would be garbage for countering what you want it to counter, but I see your point. A I don't think you understand how penetration works, damage means nothing if you cannot penetrate, but firing more shots in a set amount of time gives you more chances to penetrate an enemy tanks armor.
For example, say I added weight to a coins side and flipped it every 30 minutes, if the coin landed on the side that didn't have the added weight I got 10 bucks, so basically in a long period of time if fortune just happens to smile upon me I get 10 bucks. Or, I add weight to a side of a coin and flip it every 10 minutes and every time I get the side with out the added weight I get 5 bucks.
You would get money quicker the second way, as while you would get less money each time you won, you still have far more chances to win then the first way in a set amount of time.
Let's say in that case Jagpanthers are for skilled players. A kind of unit you can only see his strenghness while you are yourself good enough.
it's a bit the same for the Jackson in fact. But as USF you must build it and use it, there are no super easy unit that can cover the edge of your skill
The Jadgpanzer isn't for "skilled" players, there are maps and situations were it's better than a Panther (like if your Schwer got destoryed and you need to kill some allied mediums), but most of the time for players of all skill levels the Panther is a better investment. The Jackson has far more damage potential and can snipe enemy tanks far easier with it's excellent combination mobility, range, and damage. You don't need to be ultra skilled to use a Jackson, just tell it to reverse when you see enemy infantry.
If you dont destroy 260 Fuel worth of Shermans they will do the same as a KT. Not sure what your getting at. Heavies make Mediums not viable. Similar to how the Jackson makes Ostheers T3 not AS viable or desirable considering they have a heavy option.
The Jackson comparison stands on the AT level. Why would you bother to go Medium if you knew it was voluntarily putting yourself on the backfoot? I sure as hell wouldnt. Give me a Tiger clone as the USF that I can stall for! I would pick it 9/10 times.
Cost is what makes mediums nonviable (That or they don't exist) for Axis. Allies have a multitude of very viable medium tanks that heavy armor doesn't invalidate.