Firstly i refer to turtle as for other RTS games, wich mean strong lategame defense, and probably a slow but steady map contol increase. So ost with bunker spam and elephant is able to turtle as fir USF with jacksons, riflemen and the new team weapons. Pack howie is a early long indirect fire abke to move, wich means it can deterr enemy defensive positions as a LeFh or Sexton will do. It is underperforming comoared to the lastly mentioned units but its avability and cheapness make up for it.
As fir USF mobility it doesnt mean that much if your intentions are holding ground, vps or defend. Its useful to hunt diving tanks or pickup oportunities but it does not affect the faction profile overall.
USF has an early aggresive midgame adaptative late game turtle style of play.
I hope this elaboration is useful, if you already knew this things pls ignore them
pack howie its great but not for late game especially when enemy have stuka or panzerwerfer then u bulid scott and notice its only usefull when okw bois blobs but not when u need to destroy pak43 . Why usf always need to be agressive ? Just look at okw if they want they can be agressive or if they want they can be turtle faction. Or if they want they can deny your campy play style with stuka.
Anyway maybe scott need to be redesigned ? Because if u now nerf it no one will use it. I suggest like i said before delete autofire and buff range and barrage. Sherman is good enough as anti blob tool.