Americans works with combined arm but indirect fire support is absent of the equation or doctrinal with a high cost of munition. In many matches I faced an OKW easy defense core with the flak truck as milestone and it is almost impossible to take out with a doctrinal strike.
In my idea, indirect fire arms doesn't need to have more abilities to kill, but to stun vehicles and building (disable functionality for a time) or pin squad ability in a area of effect so you can follow with a massive attack.
Now, for the Pershing part of the topic, I don't know what to think, but one thing comes to my mind. MG34 is a doctrinal ability that brings small arm support to an army that should have it, same for the Panther. Why should I face OKW panther, this army hasn't been design with it but still Relic gives it at an option for gameplay - and I fine with that. In my opinion, the Pershing gives the same option, it obviously comes later than the Panther in the game. So each player has room of strengths and weakness. If you know the USF player will have a pershing, you must close the game before instead of sitting in your side waiting for CP cooldown.
@Coh2player: maybe a doctrine ability that reduce the global price for USF T4 units so you can "spam" them and be closest to the reality
