The Catharsis is a very potent fighter, yes - I'd suggest removing the blueprint for them, rather than nerfing the fighter. That way you have whatever limited number of wings you can buy or scavenge, and can't just manufacture multiple carrier's worth of them.
Then again, I also wouldn't count Sylphon as a vanilla-balanced faction in the first place. It's fun to play with, and I especially enjoy having a variety of good drone fighters (I hate losing crew from using normal fighters), but a large number of its ships and weapons just simply out-perform their vanilla counterparts (though always with at least -some- drawback, too.) And, honestly, having one mod in my set that does that is -neat-. For example, in my latest playthrough, I got one Sylphon Outcast weapon blueprint, for the Arphage - a very potent medium ballistic HE weapon. And, for a while, that completely changed how I built ship variants; medium ballistic slots went to those over, say, flak, which then necessitated finding other PD solutions, and it was just a neat gameplay shift to work with.