The sad part about the 12D Bombardier is that it's easy to fix. Remove the anti-missile system and the SRM 4, add 2 more tons of LRM ammo to the left torso along with CASE, and put a medium laser in each arm. You've doubled its ammo capacity, increased its short ranged firepower, and also secured it in case of field salvage/repair if the ammo goes up. The SRM 4 and anti-missile system are superfluous, especially in a mech whose entire idea was based around fast fire support.
That's the thing: Just about ANY change is going to make more sense than what it has: LRM-15s w/Artemis, laser instead of the SRM, dumping the AMS for an ECM or Active Probe, etc. Just like the EXT-4D, the AMS is worthless on that thing and becomes a liability.
In regards to the
Exterminator, the AMS should just be an ECM Suite. The base -4D model has
no stealth properties, despite being described as a stealth unit. And it wasn't referring to the EXT-4C, since they were made the exact, same year. The AMS and missile rack is counter to the entire premise of the machine. "Let's try sneaking around, then creating a giant cloud of smoke and tracer fire to let you know where I'm at."
Derp. The EXT-4Db is the only version that got it correct and that doesn't even have the Chameleon LPS or Null-Signature System. :-\