Isn't all this posting about "super-anti fighter weapons" and "how much do we despise fighters" sort of a show of envy?
IMHO, fighters are quite well portrayed in SE IV. They are fast and hit hard. No, I don't think that thet should have a "one hit capital ship obliterating" weapon, but neither should capital ships have a "one shot fighter group obliterating" weapon. I see it as kinda shooting at fighters with a thousand pound shell.
On the side of balance, a capital ship with 4 main guns and 4 PD's can take "technically" 8 fighters per turn. It would also force _us_, the mighty space admirals, to broaden our horizons instead of solving the thing with the conventional "mega-weapon" approach... satisfying as it might be.
Force concentration, and dedicating platforms for anti-missile, anti-fighter defense strikes me as a reasonable solution that would take care of the one-shot-one-kill, or any other fighter related business.
For those of you who still live in the 'battleship' age, remember WWII on the pacific.
As far as my experiments went, I have the Cue Kappa on the run with my new 2-shield heavy fighters, my Rommel class light carriers, and my PD Escorts.