My experience with my private version of Rebal is somewhat at odds with this scenario.
Fighters in Rebal are both faster and generally better-protected and are replaced more quickly. Seems like they should be even worse.
But it doesn't work out that way. Here's why:
1. Capitals aren't nearly as squishy as they are in Vanilla, and can be expected to take minor fighter spam without really caring a lot. Fighters are more of a threat to Destroyers and Frigates than they are to Capitals. Granted, a Reaper will still ruin your day, but not to nearly the extent it does in Vanilla.
2. Weapons, being generally balanced to deliver more damage than Flux consumed, mean that the damage output of most ships isn't quite as starved and their stats prevent them from becoming Flux-Locked as quickly.
3. Shields, being balanced around total area covered, rather than by <whatever dark magic Alex uses> generally mean that Low Tech Pirates are, while not ideal against fighters, aren't getting overwhelmed by fighter spam. Low Tech, with generally low shield areas, takes a lot less Flux damage vs. enemies that are generally hitting from all sides, because they're not getting Flux-Locked and can dish out DPS at a superior ratio to fighters. Granted, this means that some Fighters (the Lightning, in particular) are pretty darn powerful, but Sparks aren't that big of a deal.
4. Some Pirate ships are just useless against anything that masses Beams. This is a core design issue with the Hound and Cerebus and Buffalo Mk. II; it's not new news. I've recently decided to give all of them shields, because shieldless ships are really broken as anything but a joke motif, frankly.
5. Pirates in Rebal have better overall anti-missile coverage.
6. Pirates in Rebal have their own Interceptors to help out. While these are generally pretty weak, they're better than nothing.
So, with a 200-enemy Pirate swarm vs. 20 Drovers, the biggest I could find to test out on short notice without writing a custom Mission, my results were that the Pirates won pretty easily. The biggest change was that Enforcers and Dominators are both considerably tougher nuts to crack; while they have poor shield coverage areas, they have superior frontal shielding and enough firepower to largely destroy incoming fighters on their way in, and enough speed to catch the Drovers.
Now, don't get me wrong here; the Drover is still the best mid-game Carrier in Rebal; I didn't nerf it into oblivion or anything. It's great until we're in late midgame, when it starts being too squishy. But it doesn't have enough speed to avoid engagements with Enforcers indefinitely, and if we're talking about a neutral situation re: Officers, an Enforcer in Rebal may or may not win that engagement, depending on the loadouts involved, but usually does, if it doesn't take Reapers or other heavy Torpedoes.
I'm not surprised that this is the result in Vanilla, but it's not that Fighters are massively OP per se; my current thoughts on this are that the issues are systemically related to weapon balance, shields, armor rankings for roles, etc.- it's not just one problem, it's many.