Imagine if Kylo had straight up killed Palpatine at the start and been the primary antagonist. TLJ turned all the villains into jokes, with Hux being ragdolled around, Snoke dying like Jar Jar, and Kylo throwing a tantrum at Luke. Phasma not so much, but she was wasted too, so…
Getting Kylo back on track to be a genuine threat would’ve helped raise the emotional stakes and made his evolution over the trilogy more interesting.
Unfortunately…I don’t think this is editable with current material. Probably 10 years away to be able to edit that with deepfakes and video games.
That was the intention with The Last Jedi killing Snoke, to set Kylo up as Episode IX’s main antagonist. That’s what Colin Trevorrow’s Duel of Fates did as well. I think that was the prevailing idea forward until Abrams’ came back.