Alternatively, I would like to see if you could have Palpatine in TROS, “My boy, I trained Snoke.”
The idea that Snoke was just another apprentice of Palpatine, like Maul, Dooku or Vader before him would make the Snoke-Palpatine connection a lot simpler than Palpatine saying he made him. Him making Snoke still leaves us with a lot of unanswered questions. Who is Snoke a clone of? Why did he have multiple clones of him? Why did Palpatine puppeteer him in particular? Etc, etc. Did Snoke know he was being controlled by Palpatine, or did Palpatine control him completely?
I also think Snoke having his own agency keeps Kylo killing him feel like a big accomplishment rather than just another test by Palpatine.
I like the idea of changing that line.
I guess to me, I just assumed Snoke was completely controlled by Palpatine, like a suit; Snoke doesn’t exist as an autonomous person.
To me, Kylo killing Snoke is still his own act of rebellion rather than a test, as once he’s no longer being watched by his master he tries to recruit an ally.
Then the message acts as Palpatine showing Kylo he’s still in control, intimidating Kylo as much as the Resistance. Basically, Crait has both of his masters return to show that Kylo has not gained the independence he craves.