What Bobocop suggests sounds a lot like the back story hinted at in Dark Empire or Crimson Empire both Dark Horse titles.

The del rey books also had a divided empire. One with Good Imperial reformists like Palleon and the other the moffs who wanted a return to the palpatine days.

I mean really is there anything that they have not done or thought of in star wars fiction.

They did the future with Legacy and The ancient past with Birth of the Jedi.

I don't think any era has not been significantly mapped out at least in the EU that is. But if you ignore all the EU except what has been adopted into the canon film series you have a lot of room for story development.

That means things like the cartoons, comics, video games even the higher canon clone wars cartoon don't exist. Only the six films.