I could be wrong, but I think there was a Science Channel, or Discovery channel show that did touch on this subject of space combat and ship sizes and I think one of the things that was discussed (I think Dr Michio Kaku was part of this), was that small fighters like what we have in this game are somewhat unrealistic.
They could’ve been basing things on current technology, but the sizes of ships, all ships would need to be enormous for life support, power reactors, engines, armor, insulation, weapon systems all of these kinds of things. So small fighters I believe were pretty much ruled out as “not practical” and almost all ships would basically be the size of star destroyers or the enterprise for example.
During WW2, there was a theory that fighter planes would become obsolete because long range fortress type bombers with 360 degree turret coverage will murder them.
Which didn’t happen because the nimbleness of fighters allowed them to survive high-aspect fire from the bomber whereas in a low aspect environment on the fighter’s terms his multiple non-turreted (I.E. much lighter and smaller for the same punch) weapons would cause enough of a havoc on the bomber to bring it down without giving the bomber a chance to do the same.
A turreted weapon is a heavy investment in both size and weight. The more nimble you need the turret to be, the bigger the investment:
The turret of an anti-tank 20mm mg weighs several times the weight of the mg:
The turret for an anti-aircraft vulcan is a monstrous beast:
In space, you don’t have to worry about turreting a weapon if you can turn the ship around. But a large ship can’t turn fast so it has to turret weapons any time it needs to worry about small nimble ships.
Since the ship’s facing doesn’t effect it’s flight characteristics, small ships can benefit from carrying non turreted weapons, whereas heavy ships cannot. This means that a small ship’s “power to size” ratio is much higher than a large ship’s. Small ships can also benefit from a number of other important technologies (S.A. slanted armor) that a large ship cannot benefit from, bringing it’s “power density” even higher.
End result: space combat will very much have nimble “small craft”. they may not be the asteroid hugging, swag powered scooters that we see in computer games today, but they will probably be streamlined (slanted armor) to some extent.