I have watched a PIAT hit a squad of spios and volksgrens bundled up in a space the size of the center of a capture point 8 times and do no damage.
PIATS can snipe models too. Just not as "reliable" as Schrecks and Zooks. But masses of sections with double PIATS wreck infantry as well. And can shoot over sight blockers.
There's a nifty little gadget in the USF arsenal. It's really cheap and is available to the mainline infantry. It's used to obstruct vision.
Combine this with a so called flank and you are golden.
Panzer tactician is indeed a very powerful ability. But those 40 munitions cannot go into nades, weapons or abilities. Target ground is still a viable option, albeit not guaranteed. But that's what you pay for.
Furthermore, a snared tank will still have problems escaping.
The Sherman smoke is, by the way, not designed to be defensive but rather an offensive one to screen of your advances.
And how exactly is mortar smoke OP? It's bound to a squishy unit, has a cooldown, is not very mobile and needs a lot of time to position and actually land.
While USF have smoke on their mainline infantry and shermans that has way more utility.