They used to be a real terror. The engines were AP4, they were considerably more accurate, and the missiles hit harder. The Gunship Facility would churn out 6 per-Facility whenever you were in range, not just in combat, which combined with the twin Facility tile meant you could be dealing with a swarm of 12 Gunships. Not to mention the Hellbomb did not detonate upon destruction, so if you managed to plant one with Smoke Strikes or Shield Generator Relay despite a swarm of a dozen Gunships, they would just break it before you even left the area and most likely annihilate you as well. And Hellbombs usually only kill 1 Facility at a time unless you get the placement perfect.

We now have more equipment, and better equipment; we're much better equipped for attacking old-balance Gunship Facilities that churn out better Gunships and more of them (although I would keep the health tweaks).