Dual m1919/Bar REs 
Bad idea, you want to destroy USF's strongpoint?
I meant the lmg42, lmg34, rifleman m1919a6 and bren. I said that the guards (dp28) are fine.
Dual m1919/Bar REs 
the Bar is also fine. It's not considered a LMG since it the game consider it an assault rifle.
Both the bazooka and bar are obviously weaker weapon upgrade. They are meant to be dual wielded. That's why I've been asking for a decrease in the bar's price.
Well, looking at grenadiers in particular largely from a brit perspective.
You have the panzerfaust, which is enough to counter or mitigate brit vehicles until medium armour. Even end game this makes grens significant when using armour since a broken engine can spell death by pak 40 pretty easily. To be any sort of threat to armour an infantry section has to take a PIAT, thus giving up one of the weapon slots.
There's the rifle nade, which if nothing else means having to watch every engagement with grens carefully. An infantry section will rarely do anything other than find cover to shoot from since the grenades generally aren't worth the teching costs. The rifle nade also gives limited utility against MGs.
Finally you also get your LMG delivered on field. Combine that with a halftrack for reenforcement and you have a pretty potent early/mid game combo.
rifleman have access to at nade, grenade, and smoke.
Tommy have medical kit, or sight/arty. Tommies are also one of the most durable squad in the game. The mills bomb is also a clone of the US pineapple, with cheaper use cost (25 vs 30), shorter timer, and no minimal range. People keep dismissing the mills bomb, when in fact the ability is actually a much superior grenade than the pineapple.
Grenadier's faust, riflenade, and lmg42 are probably the "best" in their category, but they pay for it with durability.