I still believe that something dramatic and unprecedented for a Star Wars film needs to happen for this trilogy to be simultaneously fresh, and tell a story in keeping with operatic themes the Skywalker narrative. In my eyes, the success or failure of the ST will come down to how they deal with Rey and Snoke.
- If she's Luke's kid it'll make sense from a power-level perspective and will be consistent with previous trilogies where the protagonist is a Skywalker. However, it'll be criticized as expected, boring and tired.
- If she's related to Obi-wan (granddaughter, etc) you'll have narrative consistency where a Kenobi is a key character in all the films, and it'll mirror the OT (and PT) well. It will also require a massive retcon somewhere and I'm generally not a fan of those.
- If she's related to Palpatine you get an OT-like twist where the hero is the offspring of the villain, which could be interesting (it's possible for good to be born from absolute evil). It would make sense why Rey was abandoned on Jakku (whoever left her there was trying to protect the galaxy from potential evil) but will also require a retcon.
- If she's from a new family without any ties to characters or events from the previous Star Wars movies, it would broaden the universe so that "anyone" could be a Jedi and be the hero. The fate of galactic events wouldn't be tied to a single family's success or failure. I believe this would be a grand betrayal of the entire saga to date since it is, at its core, a story about families. It would also fail to explain Rey's great power unless they went down the next path.
- If she's a new "chosen one" or "virgin birth" archetype it'll be tired and remind people too much of the PT (which Lucasfilm is actively trying not to do). I do not think they will go this route.
Whether he's a brand new character, or linked to previously known characters, a lot of work will need to be done for us to embrace him as a worthy successor to Palpatine's villainy. There was nothing about the way Snoke was portrayed in TFA that made him appear as anything more than a superficial evil guy. He was neither a mastermind puppet master or an intimidating force. The narrative problem they've boxed themselves in here is that clearly Snoke was an important enough figure that he cares about resurrecting the Empire, but his not being part of previous movies will require a retcon that feels like a big cheat. It will also diminish the events of 1-6 (the entire premise of the ST has that problem, quite frankly). "We know the chosen one defeated the biggest threat the galaxy has seen in an entire millennia BUT NOW - 30 YEARS LATER - WE'VE GOT SOMETHING EVEN WORSE!" I honestly do not know how they solve for Snoke. His mere existence might be proof that TFA was a soft reboot that will require 10-12 to tell a complete arc.
In my perfect world, Rey turns to the dark side in VIII and kills Snoke. She becomes an absolute monster. It's a massive twist and fans everywhere shit their pants. Kylo Ren flips sides after Leia's death in Episode VIII, which has the reverse effect on him that his father's did in TFA. This sets up a showdown for Episode IX involving Luke, Rey and Ben Solo.
Hyperbole alert: Would be the laziest reveal in cinematic history if she turns out to be Luke or Han's long lost daughter. You would have to retcon TFA if this was the case.
I do agree the ST is hinging on the Rey/Snoke back stories to create an intriguing story to make the saga films relevant. It's official canon that Snoke was around to witness the birth and destruction of the Empire, so even for him to be some new evil character who lurked in the shadows of the OT is really on the nose. We have to have some connection to him imo (Plagueis/Porkins/whoever etc). It could involve the Unknown Regions and his and Palpatine's obsession in exploring the origins of the dark side?
Rey's parentage falls into the same category. Daisy Ridley seems to think it's obvious from watching TFA who her parents are, yet JJ is quoted as saying her parents are not in the film. Once again I feel she needs to be connected/related to someone/something we are familiar with (just not Luke or Leia).
I'm confident that Rian Johnson will come up with a plausible outcome on both counts. Something that will blow us away. From all accounts he has written a great story, great enough that LFL have allowed him to script EP9 as well.