Ok, random theory time. I believe Snoke could indeed be Plagueis (Palpatine/Sidious's master), but more than that, I think Plagueis could actually be responsible for creating, and thus partly giving birth to Anakin, and the entire Skywalker line.
It is said that Anakin never had a father, but was born out of the force, or of midichlorians. What if Plagueis used his ability to revive people from the dead, to instead create new life, through Anakin's mother Schmi using the force? He could be the one responsible for creating Anakin, and setting this whole thing in motion. The orchestrater of it all. The Skywalker bloodline so to speak. This could also explain why the Skywalker's are so powerful in the force, and also why they are so privy to the dark side.
I think the thing Plagueis may not have accounted for, was Sidious/Palpatine taking him out as soon as he did, which sort of put his plans on hold. Sidious may have done this learning of Anakin, Plagueis's creation, and wanting such an apprentice for his own.
After Sidious's attempt on Plagueis's life, I believe Plagueis used his powers to revive or heal himself, but that it left him in a grave, weak and horribly disfigured state (hence the scarred look of Snoke), needing a great amount of time to recoup and/or properly heal, a result of which he took a backseat and let Palpatine play out his own plan. Only after the fall of the Republic and death of the Sith (Vader and Sidious, perhaps returning some power back to Plagueis), did he re-enter the fray.
I think that could be one of the reasons the Skywalker bloodline was or is so important to Plagueis/Snoke, and Palpatine too. It is that said Palpatine created a son (Triclops) himself in a similar way, out of the force, so it's possible this is something he learned directly from Plagueis, who used the technique to help create Anakin in the first place.
This is all just guesswork and unsubstantiated theory mind, but I thought it sounded plausible enough.
