I agree with this 100%. Jackson is the lifeline of AT for USF late game and I remember how terrible it was to play Allies with WFA came out.
On teamgames. 1v1 was fine. On 2v2 you at least could finish the game before ever thinking of requiring a Jackson. Meh, good luck playing 3v3+.
The unit could be changed, the issue comes from how the change is applied. The problem is that the unit holds down the whole late game for the faction on teamgames, which have a whole different meta than smaller modes. There's no such thing as "combined arms" and smaller scale engagements, when artillery and volume of units are kings. AT vehicles can't be wiped as easily as infantry and AT gun walls. They also have better speed reaction.