I think there are differences between Snoke and the Emperor. The emperor wasn’t much of a presence in the original trilogy, a glimpse in Empire, but only really comes into it at the end of Jedi, it works, their is a shadowy puppet master who is revealed close to the end, that works quite well dramatically. He isn’t much of a character in his own right, he represents one side of the conflict inside vader, we don’t need to know anything beyond that.
Snoke is set up as more of a character in his own right, has several scenes, plans, people on both sides name check him, for him to be suddenly killed off just seems really unsatisfying. I don’t think he serves much of a purpose, Kylo’s conflict seems to be different, he just doesn’t want to kill Rey, its not some return to the light purpose, and therefore Snokes role is another thing that seems completely mechanical element to the story, rather than representing anything. Really feels like a needless character, could have just had Kylo and reworked it slightly. Just seems a moment designed to surprise, doesn’t really resonate with anything else. (Reckon it would have been better if Kylo killed him out of some pure machiavellian desire for power, to signify just how dangerous and powerful he has become).
As for Rey, I don’t mind she was not related to anyone. But disagree it was purely fuelled by the fans that her origins would have some importance, her flashbacks to the burning of the Jedi temple and then her own abandonment, her little orange x-wing pilot doll, Snoke’s references to ‘the girl’. I think it is strongly implied, and that was deliberate, maybe they always planned to mislead this way, but that doesn’t make it any less unsatisfying. Either way, nothing is really made about her search for her family, which is set up as an important character strand for her regardless of who they were
