I see many people complaining that the max fleet size isn't big enough for the giant multi solar maps. I haven't managed to play through anything over a 6player (single star) map so far, but even then I came close to maxing my troops, so I can see how the cap would be easily hit in the giant games.
So how short do you find yourselves exactly? How spread thin do your fleets become? Is it a matter that could be solved easily, like a +5% max cap for every star system you manage to fully dominate? Or will it need a more dynamic and scaling answer?