Dunedain said:

It makes sense that there would still be an ongoing fight with Imperial remnant forces (who aren't ready to just toss down their weapons because the rebels say so) after the destruction of the second Death Star, as they they try to maintain the Empire and retain control over sectors where they have a solid grasp. The Thrawn stuff would be silly, Imperial forces aren't ever going to answer to an alien, would make no sense at all, so it's good they are going with an original story line and not EU. The Empire has many competent officers that would be eager to crush any effort to fully re-establish the Republic.

There are lots of possibilities, and certainly Luke would be working on rebuilding the Jedi Order, and it would be cool if he appeared (but only if it's Hamill). :)

Imperial remnant? While I don't know how many ships are in the Imperial fleet, nor how many planets they control, a galaxy is a pretty big place. If anything, the rebel victory at Endor could have been a victory for the Empire, as the Emperor would probably have had an heir to the throne, an even more powerful offspring of the Emperor just waiting for the right moment to take power. Remember, the entire rebel fleet launched that attack on the Death Star. I can't imagine the Empire would just sit there twiddling its thumbs waiting for the rebels to escape. Also, the Emperor states outright that the Empire knows all about the rebel ship movements and strategy. It's how he set the trap.

I can definitely see an Imperial dynasty in power in the sequels, with the rebels all but defeated.