Sacred Haven of Debauchery

Could you explain to someone who hasn't played the game in a while – do these Death Stars defend themselves, or are they only suitable for destroying planets?

In my opinion, these games aren't meant to be played constantly. You see a new DLC that seems interesting, you check it out, and then you drop it until the next DLC comes out. From a marketing perspective, it's quite a mockery, but thankfully we live in the most free country in the world.