Same on the Castrums;

I would have to check the cutscenes again, but I don't think it was said they were destroyed. They were attacked, but if anything I believe they were badly damaged and not destroyed.

The only reason to attack them was to stop any re-enforcements so that we wouldn't have to deal with those while infiltrating CM. So the GCs only had to keep them busy and/or block their travel routes. I think they specifically aimed for the train line as well? That, and winning a battle doesn't have to mean ''wiping the enemy of the face of the planet''. After all, ALL of the outposts that we infiltrated are still there. The Empire took a heavy blow, but it is far from defeated.

That said, I'm not sure I want all (or any) of them to turn into dungeons. They would have to come up with pretty creative mechanics to keep them from becoming too alike.