Are there going to be static hangar defenses like in base sins? I know such facilities exist in Star Wars (there are some in X-Wing Alliance) and without them a carrier fleet can simply sit at the edge of a gravity well and spam bombers at structures. I know Golan III's get one squadron each but that is nowhere near enough.
There may or may not be additional fighter defenses beyond the Brask and Golan IIIs, but keep in mind that fighters are by far the leading cause of lag, and we don't want to exacerbate that.
Only four? In Interregnum you can get up to 12 or 14 and still have upgrade slots to make it powerful enough to fight off a decently sized attack fleet. I don't see how (with sins logic) how 4 squadrons can make that much of a difference in a space fight.
Interregnum's method of faction design and balancing is also far more aligned with the base game, where starbases are meant to be able to defeat entire fleets on their own. While stations will be significantly stronger in 1.1, I've never liked how much Rebellion was basically League of Titans and Starbases and nothing else really mattered that much if they weren't around one of those two things.