This would actually be viable if the rules are added. You'll probably only have three of them on a 'Mech or vehicle but they would be a welcome sense of realism.
Like so:
Yes, it's a GDI Titan mech, but the idea is the same. ;) The only way we can replicate this is via torso cockpits and head turrets or two shoulder turrets.
This would allow you to make Infantry even
more effective while not making them OP. Sacrifice some ammo and/or armor and boom, you've got more anti-infantry capability. You could -perhaps- also make an AMS variant called the 'dual-purpose' AMS, which can pull double duty in this sort of situation for higher ammo consumption/heat.