Maybe Snoke is ACTUALLY that guy Palaptine was quietly consorting with on the Death Star in RotJ. Think about:
A.) they're both thin, creepy, old looking weirdos.
B.) they're both affiliated with evil regimes.
I think it's pretty clear that creepy guy from RotJ was actually Palpatine's secret master, and Palpatine was the puppet. He probably foresaw the Rebels victory and hightailed it out of dodge, setting up the First Order in secret to take revenge on the Rebels and the Jedi when the time was ripe, eventually reemerging as the "Supreme Leader" that he already secretly was.
Pretty solid theory, guys.
Or God forbid, he's actually a brand new character.
__________________ I'm not going to lie: I despise children. There, I've said it.