Emperor Palpatine from Star Wars. Yes, he was a megalomaniac dictator who had absolutely zero regret for mass genocide, but what came before him? An inept Republic that was sincerely threatened by
these people with an army of
these things. A Jedi Order manned by a green goblin who gets his wisdom from fortune cookies and Samuel Jackson, who apparently couldn't express any emotion other than mild annoyance. The same Jedi Order, mind you, that forbade its own members from silly things like love. They regulated what you could
even feel. This is also the same Republic & Jedi Order that had zero qualms with using a mass produced army of
people with dubious origins, and happily sacrifice
billions of them.
Now, who commissioned that army to be made to keep the Republic safe seeing as how without it the senate was basically scrambling to not get instantly owned by the Separatists? Hmm...
Palpatine may be evil, and he may not give a shit about people, but he was efficient. Had his engineers not intentionally put weaknesses in the death star's design (weaknesses which he later fixed in Death Star 2: The Deathening) his giant comical metal laser pointer in space would have easily crushed the Rebel Alliance. He also only wanted one thing: Power, as much power as he could get, and keeping it forever. Judging by how Cloud City and Coruscant look, I'd say the deranged levels of opulence among the general populace of the core worlds remained intact, so he can't be charging insane levels of Space Taxes™. His stormtroopers seem largely well taken care of when they aren't being used as disposable pawns. Hell he even gave Vader a new pair of arms and legs and charged him with making sure that no little shits go and fuck up his tidy, efficient space empire that lets people live in opulence so long as they don't give a shit about him having all the power
and sitting on it. I mean think about it: If the Rebellion hadn't tried to interfere, Alderaan wouldn't have been blown up by the death star.
tl;dr: Emperor Palpatine should have won. Under his rulership, the galaxy was run under an extremely efficient military superpower which would have been ready to take on the threats that followed it in the Extended Universe.