Just a little correction… it´s actually a gasrat without the Al-Qaida option, which has been shifted to the Poxbursters.
But yeah, bombers work as intended. They shouldn´t be nerfed or buffed, they´re completely fine.
Chokepoints are easy abusable to kill enemies, so it´s actually great to have an enemy countering them.
I get your points about the elevator etc… yes they can block map-progress, but how about just killing them? Sounds stupid i know, but it´s actually stupid to take that elevator without clearing the room first. And it´s your choice to run blindly through the fire or not.
Even if we talk about the worst scenario, were you fight a horde in a corner or so… then yes, you´ll probably die to a bomber. But then it was probably your mistake that you dropped to early, didn´t position correctly, etc…
TLDR: Bombers are fine.