I think I'm not getting my point across. I think the Bofors is fine as is, but locking down a side of the map needs to push back the time their armour shows up.
the real problem with the mortar and bofor is how much area they lock down. More specifically, the mortar emplacement hard counter other mortar and the bofor's own suppression barrage add to the firepower.
A mortar emplacement together with a bofor is impervious to most early game assault because you can't barrage it or assault it.
the bofor's own direct fire is decent, but it's only around the level of the okw's flak truck. It's the fact that mortar emplacement and bofor have the range to counter mortar that make it OP.
even the soviet 82mm will kill the okw truck if given the chance.