I think a Death Star should still be present, but perhaps should be destroyed early into the battle. I think having it destroyed by the crashing Super Star Destroyer removes it from the scene in a convenient way, before the palace is destroyed.

Change Akbar's relief reaction shot to after a full explosion of the Death Star and then cut back to the palace, where people are evacuating knowing that the Rebels have penetrated the service channel and are heading to destroy the reactor.

If we're going to fantasize, I think replacing the Ewoks with an ignored, marginalised populace of rebel aliens living in the darkness of Had Abaddon's undercity would be a good way to finish the story off.

It's a way of showing that the Empire's citizens are prepared for a popular revolution and, in showing the oppressed condition of these people, solidifying the evil of the Empire for the viewer. I also think a properly armed group of local rebels, who know their territory of the undercity far better than the Stormtrooper recruits who only venture there to harass and dissuade them, would make for a more convincing challenge to the Emperor's "finest troops".

This group would initially suspect Han and Luke of being imperial spies. Only once proving himself to have the powers of a Jedi would the leader of this group (who could, perhaps, mention having known Obi-Wan in the past) be convinced that they are working for the Rebel Alliance as they claim.

The whole "Imperial undercity" environment would also make for a more exotic fantasy setting than the national park of Jedi.