To be completely honest I believe that the USF Howitzer's greatest ability is in it's versatility, however in an Army that oozes versatility it's really quite poor. I don't deny it's a good mortar however it's too expensive to be a mortar, honestly the developers should be expanding the USF and OKW Commanders and consider giving it to a support commander after buffing it and just giving the 80mm Mortar which is in the campaign to the USF.
The USF's hard counter to emplacements is meant to be smoke, not destruction. It's why they have it on nearly every unit they own. White Phosphorus is a kraut killer that SLOWS and damages enemy units while also screening your own allowing you to get right up in their grille... however the USF is never meant to let the Germans dig in as they are designed to stay mobile. While this is easier on 1v1's it can work on 2v2's.
The M8 and Pack howitzer are redundant yes but then again so is the entire Captains tree with the Majors tree. It's best you just spend the extra fuel on getting frag grenades for more smoke and don't let them dig in in the first place.
I get what you are saying, simple aggressiveness can deter a player from getting concentrated defenses ready and I'm good at making do with what I have. The thing is that with a light mobile army like USF, you are likely to get pushed back eventually. It's real common for players to set up near the center of the map whenever you give them the chance. From there it's real hard to make use of the mobility that make USF so Iconic as axis forces will begin deploying/reinforcing from the center of the map. You will often have to choose between either going toe-toe in the center which USF isn't designed for, or attempting to keep hold of the other two VPs. From there you either attempt for each player to hold a VP which they will eventually be pushed from by the combined might of both axis. Both options will lead to a slow grinding failure unless your opponent makes mistakes. And even after many attempts at different builds, the only one that works reliably is to simply opt for infantry company.
Premptive use of smoke is great, but it simply can't handle every situation. Not to mention building a pack should be a decent alternative to the grenade upgrade in the first place. I hate to keep bringing up the PAK 43, but it is very representative of the situation. PAK 43 doesn't give a shit about smoke, it will fire through it. Throw it behind a flak truck and you have the very situation that keeps me up at night. In my ideal situation I would take the pak out from afar with the pack. Unfortunately I would be lucky to kill the thing even after 5 minutes of constant barragment.
I don't want the pack to be the destroyer of all things like having the firepower of soviet arty. Just that it be able to effectively loosen up concentrated defenses by picking off/forcing away a MG, or AT gun here and there without being 5 feet from them. So I can actually make use of the mobile forces I do have to exploit the weaknesses in the defenses it creates. But right now with current stats, it struggles heavily to do damage to anything that isn't running right towards it.