Besides, the game even GAVE all you raving fighter-fanboys what your asking for. Tiny and S-class hulls. If you want 'fighters' do what I did.
Actually, no. Tiny and Small hulls in particular have some fairly hefty tradeoffs between speed, range, durability, and firepower, and as such if you want a fast fleet are impractical to use. The purpose of a carrier would be allowing the use of such hulls without needing, for example, to drop your standard 4 engine and 6 life support components on them, and in exchange for the firepower that that gives you, you end up with a relatively vulnerable large ship (or ships) as the carrier, and perhaps it takes a round or two to deploy the 'fighters' thus carried with the fleet.
They could be dirt cheap and have high thrust to mass ratio because they don't need FTL, damage control, gravity, or extended life support.
At the very least you would need some form of artificial gravity if you want accelerations much over a few gravities (if the craft is piloted by a living being; here I use 'gravities' to refer to acceleration normalized to the standard gravitational pull of the homeworld of the species piloting the craft rather than the Earth standard gravity). It doesn't matter if you have a thrust-to-weight ratio in the millions if actually using it turns the pilot into jelly or the ship into shrapnel, and artificial gravity of some sort is one of the few 'reasonable' ways to prevent occupants from turning into jelly; preventing the ship from becoming shrapnel is more of a design and hull integrity concern.
Pretty much what they're good for in real life. Cheap power projection. I'd see fighters in space kind of having a reverse history to fighters on earth where they'd make up the bulk of your early navy, but would take more of a secondary scouting/support role as larger and more advanced ships become available.
This might be reasonable for, say, planetary surveys or the like, but as DsRaider said, there isn't much purpose to a scout craft that is slower than its parent craft, especially since superior sensors tend to be larger sensors in real life (meaning that you can't have the justification of a scout craft that carries a better sensor suite than its faster parent craft except in the case of a technological divide between the parent and child craft - e.g. a relatively obsolete warship which is able to carry a small craft with the latest and greatest in sensor technology. There is then a question of why you'd do such a thing - both from the why you put a hanger on the ship in the first place perspective (unless we're looking at a carrier), and from the why you didn't just upgrade the sensors on the big ship perspective. A decent sensor suite will always take less space than that sensor suite plus room to store an associated platform to carry it will.
Carriers as a way to make small and tiny craft into reasonable components of my fast fleets are something I'm fine with, if it comes with an associated disadvantage that makes it more or less balanced against my normal fleet of fast battleships. Carriers with a special 'fighter' weapon type are also something that wouldn't particularly bother me - it wouldn't really add anything, but it wouldn't hurt either. As for the camp that says 'nothing should be added to the game if it doesn't really add anything', I direct you to the Terror Star - a weapon of mass destruction that I used exactly once in the years that I've had GCII, and for which I also always voted for the ban in the United Planets. That is something that added nothing to the game, at least not for me, and yet I'm sure if we put up a thread that says "Terror Stars should not be in GCIII" we'd find people defending the stupid things.
All this being said, I am neither for nor against the addition of carriers to the game. If small and tiny hulls remain nothing more than short-range gunboats, that's fine. If they become short-range gunboats that can be carried with heavy ships to serve as fighter analogues in big fleet battles, that's fine too.