By being a jack of all trades the destroyers in FS are the worst compromise between firepower and fighter capacity, making them worthless overall.
Apparently you haven't played Freespace 2, or else you would have heard of a little ship called the Orion, which, when broadsiding a target, can destroy a Sobek with two
BGreens and one or two slash turrets, easily bringing some of the most effective firepower in the GTVA to bear with a quick rotation.
What the GTVA needs is a carrier, its really that simple, something designed to launch, recover, and DESTROY fighters.
And, if you look around in the various user-made campaigns, you would find that several carrier designs have been implemented and completed.
With subspace travel there is NO REASON why ships of the line (destroyers) should ever...EVER carry fighters...EVER.
What, so you say that, just because fighters have a subspace drive, they should never have to dock with a larger ship except a rare, multi-billion dollar carrier? The purpose of the fighterbay in a destroyer is the ability for a destroyer to support itself in a direct confrontation with enemy capital ships by using its smaller squadrons to ward off enemy fighters and bombers and disable enemy turrets. Also, they allow the destroyer, which can be more commonly produced than a massive carrier, to reinforce its battlegroup with quick, easily-delivered firepower through fighters and strike bombers.
If the GTVA had dedicated ships of the line, say a Hecate with actual firepower supported by multiple Deimos corvettes and screened by fighters and cruisers they would pwn, but instead they suck.
A battlegroup of that
size is just far too improbably and inefficeint. Sure, they would kick some serious ***, but in one place at a time only.
And Hecates, despite what many say, has some serious firepower, at least in its forward arc. You know those two turrets on the front? Those are beam turrets
. When a Hecate jumps in, it just simply maneuvers to put a Shivan/NTF/Vasudan/HOL target in its sights, pushes the button, and makes the bad guy go away.
A destroyer that sacrifices firepower, armor, speed or maneuverability to carry fighters into a direct-fire(IE line of sight) battle = BAD!
A destroyer that carries more firepower, significantly tougher armor, speeds of over 15 m/s for its enormous size, and can almost turn on a dime in-game, and be able to deliver several squadrons of lethal fighters and bombers at various targets = NOT BAD!