.. Yea to lose a Jackson to a p4 the usf player would have to have its engine damaged and attacking the ground in a different direction.
It has all of the power of other TDs, with all the advantages of the usf with none of the weaknesses of either except that the main gun doesn't damage infantry
What are the advantage of the usf?
In fact if you look at all 3 allied faction's design, Jackson is what it is on top UKF and Soviet TDs version for some good reasons.
Soviet have stock sprint on Cons + atnade combo would make a Jackson like too powerful on Soviet roaster, the SU-85 doesn't need speed if the Cons have it. Katy also have a role here since its a perfect unit to blow away enemy defenses from far, that hmg covering the flank for your cons or that pak40 for your T34 to flank. Su-85 doesn't need to be super mobile when other unit can do it for them.
UKF is all about late game, there is no need to draw a picture about what would be a Jackson like Firefly with a Churchill or Comet soaking the damage. We could even consider the Armored car since it has a really good main gun vs medium tanks.
Then USF, well what does have USF that have speed or long range high profile damage or a ton of hp to soak damage and simply that can brawl in the front. Hum? No-thing.
Now I'm not saying this is good design, but make it for the Jackson to be what it is.