Mortar Pits have a lot more HP than shocktroops, though. They also need to be vulnerable to something. If it's not indirect fire, and it's not AT guns sniping them, they have to be vulnerable to infantry.
I do agree that it does need a certain weakness and a small arms weakness makes sense but it's a bit too vulnerable under the current stats. I did a test of this and it's quite shocking. I placed two UNUPGRADED Vet 0 Ostheer Pioneers (A realistic assault group size for most players) next to the upgraded British Mortar Pit. It went down in three bursts. Then tried with Sturmpioneers to see it go down in two.
Next with two Vet 0 Panzergrenadiers and then finally two Vet 0 Assault Grenadiers afterwards. It went down in a mere 1.5 bursts from each. That's horrifyingly fast. It makes the USF Fighting Position look like a hardened bunker.
There are light vehicles with more armour and they can still be considered counterable with Small Arms like the Soviet M3. YES, they have less Health but you can still do noticeable damage without it vaporizing.
Combine the fact they have seemingly high health and the now slow repair rate of Sappers and they are just a liability to try and keep alive. I am willing to accept Small Arms as a counter for Mortar Pits but certainly not to this extent.
They don't need the armour of the live version (Which is 5 Armour) but they need to have at least
some resistance to show their Sandbags aren't just filled with air. Hell, I'd go no higher than 3 Armour (4 Armour with the Emplacement Regiment).
I'm sure you guys would have agreed if you were able to do more testing before this version was released early. Good thing is, we can keep tweaking it until it feels right since this isn't an official Relic release.