There is no role for the firebeetle in the Cybran arsenal. For early snipes and raids they have jesters. For ambushing armies they have deceivers and normal land units. They have renegades with high aoe for anti-army, sniping ringed mexes, killing lots of engineers, etc. They have corsairs for sniping units and pgens. They have TML-4, the fasted firing and flying TML that also splits into 4 missiles, for sniping structures or anything you can hit with it. They even have a cloaked and stealthed laser ACU for doing whatever with. Anything you want to do, Cybran already has a better tool for it than the firebeetle.
The only thing fireebeetles do is confuse noobs who don't understand how cloak and stealth work, or remember them actually being good some time in ancient history. Nobody else ever uses them.
Despite firebeetles being the most pointless unit in the game, they get the most attention from everyone. Keyser, the Game Councillor and the most intelligent Frenchman in the entire FAF community, has spent most of his adult life rebalancing firebeetles. Each balance patch totally changes the unit to do something even more bizarre and even more useless.
The only sensible thing to do is remove them from the game so that so many great minds are not doomed to eternally rebalance them and talk about them on the forums. It might also be possible to reskin them and give them to another faction that doesn't already have superior units in every possible role.