Yavin IV Blows up, Everyone Dies, is the Universe Better Off?
Sidious conquers everything with a fully functional Death Star and no one to oppose him. Is the Star Wars universe better off considering the multiple of wars fought post-Empire like the Vong war?
Or are is the Emperor too tyrannical?
EDIT: By "everyone" I mean the Rebel Alliance.
"What the Empire would have done was build a super-colossal Yuuzhan Vong–killing battle machine. They would have called it the Nova Colossus or the Galaxy Destructor or the Nostril of Palpatine or something equally grandiose. They would have spent billions of credits, employed thousands of contractors and subcontractors, and equipped it with the latest in death-dealing technology. And you know what would have happened? It wouldn't have worked. They'd forget to bolt down a metal plate over an access hatch leading to the main reactors, or some other mistake, and a hotshot enemy pilot would drop a bomb down there and blow the whole thing up. Now that's what the Empire would have done."
- Han Solo
More seriously, in Allegiance the Empire massacres a village of aliens because there were reports of Rebels in the area. In the Force Unleashed we see a Moff who likes to hunt Wookies in his AT-ST, while using Wookiee slaves in construction.. Non-humans were second-class citizens and non-human slavery was legalised. Only 'pure' (i.e., those made exclusively by Humans and with no help from nonhumans) works of art were allowed to be produced, viewed, and spread, since only Human culture was worthy enough to be allowed to prosper in the New Order. Non-Humans were 'actively discouraged' to participate in government or join the Imperial military, and Human governors and moffs were placed in command of nonhuman worlds and sectors.
**** no would the Universe have been better off. There would have been more people in it, probably, but they would all be lesser for living under such a regime.
I think it would be more subtle, if it was Plagueis, who didn't have anti-alien politics.
Here are some less obvious examples.
Nogri would forever be assassins giving free service to Empire because they help them restore their planet, when in fact Empire was intentionally polluting their planet instead of restoring it. And advantages of other species would be similarly exploited.
Yuuzhan Vong would be completely wipe out instead of realizing the mistakes in their way and becoming peaceful culture.
And most important there would always be rebellions, which would result in a lot of deaths. One rebellion resulted in Alderaan being destroyed, why would it be different for other rebellions?
It's be a crappy couple decades before the Vong showed up, with plenty of casualties. Mon Cal'd be blown up for certain, after Yavin, probably several other worlds.
If there weren't any rebellions, the Emperor would *make* more as an excuse to cause fear.
There'd be wars with the Hapes cluster, Hutts, eventually Chiss... all a matter of 'when'. And with the Death Star in the ring, the result would often involve destroyed planets.
And knowing Palps, while he would crush the Vong, he'd give them enough room to work for the populace to see what they were doing and let them cause lots of damage, so they'd be more impressed when he crushed them. Maybe put a scapegoat in charge of defense of that area first, assign some people who represent potentially troublesome views.
It wasn't just that humans were superior: human men were superior. Let's not forget how few women were given any kind of true power under the empire and how the moffs conspired against the females who rose to what they considered to be too great heights.
Nothing good would have come from the Empire remaining in power under Sidious.