The more I think of it the more I like the idea of bringing Palpatine back in some way (though not this way). If the ST is all about legacy, and the OT heroes all find the strength and confidence in their proteges to move on knowing the galaxy is in good hands, wouldn’t it be interesting if the antagonist is an old villain who absolutely refuses to move on in any way?
I think a simple way to have gone about this would’ve been what Matt Smith’s rumored role was to be, to have the spirit of Palpatine possess a host body, rather than have his literal body still be around. To be fair, it almost seems like his spirit is attached to his dead corpse, the white eyes make me thing that’s the idea, but it still a stretch to think his body remained in tact enough to extract from the ruins of the Death Star.
Something I honestly liked from Trevorrow’s script was Hux collecting lightsabers and other Jedi/Sith relics. I could see how his rivalry with Kylo Ren makes him wish he had that power to oppose him. You could’ve tied both things together by having Palpatine’s spirit calling out to Hux (maybe from Vader’s helmet aboard the Finalizer), and offer Hux unlimited power in return for being his host. It just ties into their rivalry well and after how much Hux was thrown around in TLJ, I could see him selling his soul to try and overcome Ren. And between them and the final confrontation, we could see Hux’s body become more like Sidious’ as the dark side quickly corrupts him, essentially destroying his body, and then Palpatine could throw him away and jump into a more suitable host.