The Jackson would need a price increase then, 240 pen at max range + it's great mobility would make it out class every medium TD in the game in every way except armor.
For instance, 240 at max range is almost 100 more than the JPIV at max range and the SU-85 at max range.
No it wouldn't. The compensation for more pen is less damage.
Other TDs might have less armor but they have more HP and armor.
To put things in perspective, the only tanks in the game with more than 240 pen at max range are the Jadgtiger and Elefant.
At 240 pen at max range the Jackson would have the best long range penetration of any non-doc tank in the game, as well as all doctrine tanks in the game except for the two previously mentioned.
To put things in perpective, it's the only tank USF can get that is designed to fight tanks. It's the only vehicle USF have that is able to fight against Panthers/Tigers (and it doesn't even do a great job).
Even with 240 pen it wouldn't be the best non-doc TD. No armor (only small arms resistant) and low health make it extremely easy to destroy. SU-85 and JPIV might have less pen but they don't get 3-shotted so easily.
The JPIV also has more armor and fights against tanks with less armor in general which makes it the best non-doc TD in-game IMO (even if the Jackson had 240 pen).
Uh, the Jacksons mobility means it requires less micro, not more. It can easily escape a sticky situation in a way the SU-85 and JPIV cannot.
Making the Jackson literally the most cost efficient best tank killer in the game that also comes in roughly the same time Ostheer first gets T3 would make Axis medium armor more rare, not less. It would also turn the Tiger into a joke, since the Tiger would be helpless if it's armor was getting penned every time by a tank it couldn't even touch.
What makes the Jackson ~okay~ versus heavy armor is the trade off of damage versus pen, meaning that when you pen you fuck a tank up hard, making it's damage reduced but giving it garenteed penetration would mean there is literally no trade off.
The last time I looked at the stats, SU-85s and JPIV had enough HP/armor not to get 3-shotted by almost anything in the game.
As others already said, Jacksons already pen every OST T3 vehicle with 240 DMG. Increasing its pen will not affect T3 in a negative way but reducing its DMG will make it less powerful vs mediums.
Put a PaK behind your Tiger and see how the Jackson can't do anything.
The trade-off is reduced DMG. Even with 240 pen it's not guaranteed that it will pen a Tiger/Panther (only with HVAP rounds).