Good arguments. I mean, I personally prefer the Sith collective consciousnesses idea. I’ve suggested ways to emphasize it even more, like having Palpatine’s voice sometimes be layered with multiple echoing voices. Like all the Sith are speaking through him.
It just seems like they barely touched on that idea in the film. Like, taking it out wouldn’t effect the story at all. And no one even talks about it. It’s just that “Palpatine” has returned. Palpatine this. Palpatine that.
It would be an interesting thing for Kylo to explain to Rey. Suddenly, the idea of defeating Palpatine seems that much more challenging, if cheating death if something he/it has done for a thousand years.