"who Snoke is"?I like that now both the dark side and the light side have "rookies" that will get extensive training. Looking forward to the inevitable confrontation(s) after that. In many films the villains are already top-tier, with the protagonist being clumsy/weak/unprepared/etc. Now it seems we will get the journey for new potential masters on both sides. Kylo is an interesting villain; I hope they do his transition to a more seasoned and intimidating villain well (if at all).
New characters are all very likeable and have something distinct about them, which is great. This films sets up the stage for what is to come in an excellent way.
Also, regarding the people saying the story has not been written yet. Really? I mean, they must have the basics set in stone right? Making a new script of how events unfold does not mean they do not have the background stories ("lore") present already. I honestly expect them to already know who Snoke is, whom's daughter Rey is, what Lukes plans were/are etc.
I'd prefer him to be just an evil dude named Snoke, maybe a former high ranking member of the Imperial Council, but I seriously hope that there isn't some reveal surrounding him.