Well I mean Palpatine's first goal was obviously immortality. And it was something the previous Sith Lords, Plagueis and even Tenebrous, seemed to advocate as well but unlike Palpatine they had the common Sith decency to accept their death. Clone bodies clearly weren't a workable long term solution for him sadly.
The main idea behind the Death Star (and much of the Tarkin Doctrine) of course was that the Fear would actually help keep the Empire stable. And why did he want it stable? Because Palpatine wanted to travel (with his loyal Vader) about the Unknown Regions and other areas looking for juicy lost Sith knowledge so he could increase his power. Obviously in Legends and the like he did acclaim a great deal of power poking about the Deep Core and the like. But there was still so much else to find.
But if he was busy running a galaxy (made all the more dependent on him thanks to things like Battle Meditation) then he'd never have the freedom to spend months, years or longer journeying forth into parts unknown looking for the secrets to acquiring more and more unlimited power.
But yeah it'd be interesting to see the whole Dark Empire thing come about. Was he actually fueled by dominating other people or was it just a beneficial byproduct and something that fueled his ego more then fueled him in a literal sense? A Dark Empire where he's extremely powerful (as Godlike as a force user can be with de facto immortality) and using Skywalkers and other force bloodlines as his noble lackies definitely can help keep his Imperial Empire transition into a stable Dark Empire. But... Sith also have that habit of backstabbing. It's how they evolve. As lackeys go, Vader was impressively loyal and ruthless but he was more then down with betraying the Emperor when his son showed up.
So Palpatine dominating all contenders makes sense. He doesn't need to turn everyone into a Nihilus style drone, but it'd be interesting to see what swaths of the Imperial government, military and power brokers would be so dominated as to not be a threat to him or even brook the idea of rebellion. Palpatine (both in Legends and Disney) unlike other Sith preferred manipulation, whether through fear or despair or anger or even pride in order to compel others into obedience as opposed to some sort of brute domination with force powers. So not really drones, but slaves to his will nonetheless.
And once he's attained enough power that on a personal level he's unchallenged by any of his powerful lackies (Vader and/or other Skywalker ilk) and his Dark Empire is secure through a combination of force and manipulation that there are no polities that can challenge him (like it's obvious after the Rebel Alliance is done for, he'll take out everybody else, Hutts, Black Sun, Hapes, Vong etc, then he can start resarching ways to go extra-galactic.
But again, if he's going to be spreading his Dark Empire extra galactically that'll require a lot of time away from his home, so again, nice and stable while he's gone. And honestly having servants who can think for themselves (ie Thrawn and Tarkin and the like) is probably far more preferable then a bunch of Dark Force dominated drones controlling the levers of power as he's absent. Especially since there's still other threats out there (at least in Legends you have stuff like Abeloth and A'Sharad Hett wandering about) who could take advantage of a Dark Empire inured to being slaves to any Dark Lord of sufficient power.