Here's another question...
...
Who the HELL was Snoke? Where did come from? How did he get so strong in the Dark Side? What happened to him to screw him up so--the damage to his body?
I hope we never find out. They ruined Boba Fett and Vader when they showed their origins. Han Solo, possibly, too next year. Some characters don't need an origin story - they work better when they're mysterious.
I don't think we need to know what he was like as a child, but there really has to be some context provided for Snoke. A dark side force master of that magnitude, who takes control of an army of space nazis and controls a significant percentage of the galaxy, is
A Big Deal. To leave his nature and origin vague, as if it doesn't matter, is to suggest that the galaxy is actually full of them--that any group of space nazis with a fleet of ships will almost inevitably find a dark side demigod to lead them.
That said, I feel pretty certain we've not seen the last of Snoke. All you have to do is to look at him to see that he's been killed before, at least once by having his head crushed. I don't know how he's going to get reanimated or reassembled, but you don't tease his ability to survive like that and then kill him off with one slice, especially considering that Darth Maul already overcame an almost identical injury. In fact, I speculate that the entire reason Snoke's background has been left so vague so far is to avoid making it too obvious that simple straightforward mortal wounds are not enough to kill him permanently. Once he comes back and his background is made somewhat more clear, we'll be shaking our heads at how stupid Kylo has to be to have not seen it coming.
Snoke was built up as The Big Bad over a movie and a half, then summarily dispatched. I don't buy it. His bodyguards were more formidable than Snoke turned out to be (that was a pretty great fight scene.) It's like Rey's parents--the search for her parents was the defining motivation for her for a movie and a half, but we're supposed to accept that plot thread wrapped up with "they're nobody?" Pull the other one, it's got bells on. If her parents were "nobody" we would have seen them by now, in her memories or her vision in the cave. You don't make a big deal out of hiding "nobody."
Besides, we are certainly going to get more backstory on Ben Solo being seduced to the dark side, and the nature of the "Knights of Ren (and Stimpy)."