Having recently played Homeworld 2 again, i'm quite impressed at how well you captured the feel of the various ships. I also had my doubts about the Corvette when looking at the stats but suffice to say when the wingmen flew in that all changed, quite fun to fly around in.
Anyways, i wanted to make a balance suggestion. I've noticed that the Homeworld series seems to use Cold War/Modern classifications for the various ship types while Starsector uses WW2 era classifications.
Simply put, during the Cold war, Modern missile systems and Aircraft carriers made large ships like Battleships obsolete and they were replaced by Destroyers and Cruisers with Guided missiles. Destroyers and Cruisers became capital ships and their size and capability increased, some Destroyers being as big as some Heavy Cruisers.
As for why this matters, we'll look at the Vaygr Destroyer. In Homeworld, Destroyers are classified as Capital ships and they are the main stay of a fleet along with Frigates much like in modern navies. They are also some of the biggest ships you can build after the Carrier, Shipyard, and Battlecruiser. In your mod however, they are Destroyers like their name suggests and have been balanced as such. While HM's Destroyers can tank quite a lot of damage and take on multiple frigates, in SS due to their DD balancing they are outgunned due to it's shorter range, it's armor somewhat weak, and slow for a destroyer.
Thus, I would like to suggest you bump up the various Homeworld ships up a "Class" or two. Corvettes to Frigates, Frigates to Destroyers, Destroyers to Cruisers, etc. Although i think Carriers are fine as Cruisers.
Although doing this would be a lot of work no doubt, i think doing it early would make balancing them easier later down the line. Their performance could be much closer the balance of Vanilla ships and other mods. If not i assume some of the smaller ships would be too powerful while the larger ships too weak comparatively.
One last thing, you've noted that you wanted to nerf the Corvettes a little, maybe reducing the wing size to 3 and lowering the damage of the Pulsar cannon to make it weaker against armor?.
Apologies for the long post, especially if i unintentionally sounded condescending. I quite like your mod and would like to see it reach the point where i can fly the Hiigaran Battlecruiser.
Cheers mate.