I have been thinking about it as a broad idea where Armada could go in future waves. While introducing new fighter packs is a decent route there are not a lot untapped capital ships from the Civil War era. At least not without dipping into older Clone War Era ships that were replaced because they were outdated. There is also the possibility of cross faction ships as it is established the Empire did use ships we normally associate with the Rebellion and the Rebellion did capture some ships from the Empire and used many existing Imperial ships in th New Republic era.
I think a better route may be in releasing something more like the Veteran packs from X-Wing where we get new titles and upgrades for existing capital ships. I think something that also would be healthy for the game is a a robust campaign system that demonstrates the superior numbers and logistics the Empire enjoyed while showing off the strategic flexibility the Rebellion had in being able to pick and choose their fights by being more mobile and not having fixed places they needed to defend.