Dark Avatar II looks really good and I like a lot of the advancements made.
however...PLEASE PLEASE PLEASE, in the true sequel or the next expansion..
add Space Carriers as capital ships to carry/protect/repair smaller fighters! In GalCiv II there was not much point in using fighters in most modes of the game. I know some people like to argue this, but you're wrong

. Most players of the game quickly discover it's extremely difficult/borderline pointless trying to run an effective military based around smaller ships, particularly on the advanced difficulties...which is frustrating because starfighters are one of the cooler aspects of the whole space sci-fi genre. They should be a very viable military strategy in what is the best galactic conquest space sci-fi game out there!
Even with Capital ships costing more logistics and taking longer to build in Dark Avatar, it's still basically going to come down to who can build the largest fleet of biggest ships the fastest.
By adding Space Carriers, you could make it so that fleets made primarily of Space Carriers would be able to overwhelm EQUAL logistic fleets made primarily of large capital ships. It would become a viable strategy for countering capital-ship-stacking superiority fleets.
For example: a fleet of four large Space Carriers would have a tactical edge over an equal logistics fleet of four large battleships by having a logistical bonus. How? By making the fighters housed on the carriers NOT count towards the logistics total of the fleet! Then you just carefully design how good the logistics bonus would be by limiting the number of fighters each carrier can carry (which when designing your ship is based on the number of "hangar" modules the carrier has). The number of fighters then presents a tactical edge based on the NUMBER of small targets presented to the small number of larger, more powerful capital ships.
In turn, fleets made primarily of Space Carriers would be vulnerable to fleets with more balanced arrays of ships that are better able to deal with large numbers of small fighters. Ie the same fleet of four large space carriers that has a good tactical bonus over the fleet of four large battleships due to overwhelming number of fighters presented, would fall to a fleet of two large battleships and five medium corvettes that are better able to deal with the larger number of small targets.
You could toy with other interesting bonuses as well. Carriers could be able to repair fighters faster than normal, making them good choices for deep assaults in enemy territory where they can recover from damage quicker.
There's so much you could do with it and most of it would slide in pretty easily to the current combat system!