The Empire is Operating in the Outer Rim
This development makes plenty of sense while offering plenty of storytelling opportunities. Palpatine concentrated his scope of influence mainly on Coruscant and the Core planets while mostly neglecting the Outer Rim worlds. It may still take a while for the rebels to expel the Imperials from the inner systems, but once they do, it will be tougher for them to exert control over the more distant territories, allowing Imperial sympathizers to hide out there.
This is the reason that Wedge is visiting these outer worlds in an effort to sniff out Imperial bases that are operating under the radar:
"“Somehow, the remaining factions of the Empire are still fueling their war effort even months after the destruction of their second battle station. Wedge had the notion that they must’ve moved out to the Outer Rim—study your history and it’s easy to see that the seeds of the Empire grew first out here, away from the Core systems, away from the prying eyes of the Republic.”"
Although Palpatine likely ignored any of the peoples located in the Outer Rim, it’s possible that he didn’t totally neglect it. I wouldn’t be surprised if there were elements of a back-up or failsafe plan located on one of the planets, hidden from the view of Capital officials. This could range from anything to a secret army, a devastating superweapon, a powerful technology, or some other kind of threat.
Meanwhile, we’re also learning about who’s still sticking around with the resistance…
Next: An Old Friend is Back