just because it was in the preview doesn't automatically mean that it's fine. No one caught the issue with t34-76 mg buff until it got into a larger testing base.
and giving the usf a crappy mortar seems like it's doing it for its own sake. It feels like an obsession with providing them with a mortar without regarding for design or balance.
I also say that even a crappy mortar will be too much for the early USF. It's giving them extra option and strength at the stage of the game where they already dominate. A crappy mortar doesn't help the USF with their weak late game while buffing their already powerful early game.
If USF player goes for 2RF+1Mortar it means you can easily punish him for that becasue your field presence will be greater.
USF needed mortar to be able to fight with HMG/buildings without mandatory nades - that was the point of mortar.
USF were forced to go for nades always vs HMG/Buildings so putting mortat behind nades does not have any sense becasue it was to be able to skip nades.
It's not good when a faction is forced to do something becasue there are no other tools.