One could argue the fact that Pak Howie is locked behind a tech path and the fact that USF has to face MG42 from Minute 0 means that they at least deserve a barrage that is equal to other mortars. When you factor in that Pak Howie is getting nerfed this patch, Scott autofire is getting nerfed this patch, Calliope is getting nerfed this patch then USF artillery needs something to compensate for LT builds where you're going to using the mortar first and foremost.
Not really.
Ostheer have the HMG-42 because gren loose to riflemen. If USF can counter the HMG with cheaper mortar that will leave back into Riflemen beating the Grenadier and one would have to buff the grenadier to compensate.
As for Pak the nerf are hardly effective since it true power comes from its vetted barrage, WP and HEAT. The only reason why it not completely broken it is its High XP value but not matter how you look at it is best "mortar type" weapon.
As the fact the Pak has tech that mean little because it was locked behind intentional from faction design and the Tech revamp made USF allot more flexible already. On the other hand Ostheer where original designed as combined arm faction and they currently losing even in their own game.
Calliope's "nerf" means very little since all artillery received similar nerf.
Button line is USF actually have more stock option the other faction that includes: T0 mortar, Pak howizter, Scott, Major barrage (and I would also add the Sherman HE).