There are two, quite frustrating things about those emplacements:
1) Indirect fire rekts them way too much. You spend a lot of resources on it, and someone takes it down like you kill enemies in an FPS game. Point and click.
2)That brace ability, which means that a player can perform a large scale operation to draw attention of supporting forces with weaker part of the army and then quickly attacks the emplacements with supposed counters like AT guns.
And guess what? Enemy clicks brace, and...
So maybe brace should be removed, while emplacements should get immune to any sort of indirect fire (+ maybe little help against flame grenades)