Thinking about the coming awesomeness this Thursday and why they will blow the prequels away; I think that the downfall of the prequels can, in part, be attributed to the fact that the only established charactes who you already knew were Yoda and Obi Wan. Yes, R2D2 and C3PO are in them too but they are just sidekicks. You "knew" who Anakin was and you know what eventually becomes of him but there hadn't been any space dedicated to Anakin (not Vader) until Episode 1. Same with Boba Fett in Episode 2 but you aren't meant to know anything about him. That's why he was so bad ass and so loved in the Holy Trilogy. You also knew Princess Leia had an adoptive father in the OT but how did he end up adopting her? There may have been some literature during the course of the OT that mentions him by name but I don't recall.
Same with Owen and Beru; they were relatively minor players in Episode 4 and Episode 2 and while I think the backstory of how they came to be related to Anakin was a bit weak at least they established the relationship and its a lot more believable than Owen being Obi Wan's brother (as mentioned in the Return of the jedi novelisation). Oh, and Chewbacca but I think this was deliberately done. Lucas always said that he envisioned the final land battle of Jedi taking place on a planet of Wookies rather than Ewoks so he made up for that by having a set piece/action sequence in Sith. And you can't really have Kashyyk without showing Chewy.
I remember being a kid and wondering how The Emperor had managed to become The Emperor and how he managed to be more powerful than Vader. And you KNEW from Darth Sidious' first apperance in TPM that it WAS The Emperor. So while it was good to see Palpatine and Vader's relationship fleshed out there wasn't a great deal of mystery about it.
But I digress; aside from those established main and supporting characters I think most people just had a hard time wrapping their heads around all these new people that populate the universe and what purpose they served . In the sequel trilogy, you already KNOW who the key players are and while we don't know the full plot at this stage you KNOW the relationship between the characters and what purpose they serve.
But going beyond that; this wouldn't be the movie that we are expecting it to be if the key players (Han, Luke and Leia) were just dropped in to the plot and expected to carry on as normal. They have to DEVELOP and EVOLVE to serve the story and I don't think there's going to be a better example of this than Han. He goes from "hokey religions and ancient weapons are no match for a good blaster at your side, kid" to "its true. All of it. The dark side. A Jedi. They're real."
With the plot of the movie revolving around trying to find the reclusive last Jedi, this makes me wonder how this change in attitude from Han means about the development of Han's relationship with Luke and how it fits the new film. Is he genuinely concerned for the whereabouts and well being of his friend and what motivates him to help Rey and Finn find him?
Its also rumored that Han and Leia are estranged when the movie kicks off. Why? Something to do with their kids? Something to do with Luke? Something to do with Han's secret wife (yes. It's in the new comic canon)?
And on Leia; she is a Skywalker so is strong with The Force. But in episode 7 she is a general. Could she have been a Jedi? If not then why not? By the time she finds out in Jedi that she has a power that she has never understood she would have been in her early to mid 20s. Luke started training at the same age despite being "too old" . Was it too late for her start? Did she train in some capacity in that 30 year time frame and did she sever connection to the Force for some reason? Something to do with one of her kids going bad? Something to do with her twin brother going bad?
And finally Luke. Why is he hiding? What happened to him? Is he evil? Did he have children? I can't even speculate on him and his relationships with the others because his character is being so well protected all anyone can do is speculate as to what his role in the new film and trilogy is (Hamill has already said he is in Episode 8 and has already started filming). I guess I'll break it all down and speculate on his future involvement in the wee hours of Thursday morning.
So I'd wager that the average movie goer and Star Wars tragic alike are going to relate more to a story with these established characters than to a film where the seeds have to be planted all over again. Even with all the characters and cameos that Abrams is throwing in for the sake of nostalgia (as Lucas did with some of the aforementioned chatacters in the prequel trilogy) people are going to relate (maybe us who are more steeped in the mythology of the films than a regular movie goer).
Take Admiral Ackbar for instance; these days id say he is more widely know not just in the Star Wars canon but in popular culture in general thanks to Family Guy! "Its a trap" to me is on par with "you're gonna need a bigger boat" as a throwaway line in common venecular. Oh, and i myself got a little bit excited when I saw Nien Numb flying an X Wing in one of the tv spots. I always knew he was going to make an apperance but I'm used to him copiloting the Millennium Falcon with Lando so I had a bit of a fan boy moment.
At the same time, there might be one bad performance from one of the new characters that might make or break the movie for some people. What if Daisey Ridley turns in a performance on par with Sofia Copolla in Godfather 3? From the looks of things it looks like she is going to be the focus of the film and perhaps the new trilogy. If she's not convincing or if the story (in terms of Origins/relationships) that has been developed for her is weak (midichlorians, anybody?) then what does this mean for the well-being of the new trilogy? I mean, people are going to see them anyway but in terms of criticism episodes 8 and 9 might have lower than normal expectations placed on them based on the strength/weakness of TFA
Another thing that strikes me as interesting is something Abrams said in a few interviews; when you first watched Star Wars there was nothing that hinted at the plot twists and relationships that are revealed in Empire and Jedi. There is the relationship between Vader and Obi Wan that you know existed but you didn't know the backstory of that relationship. Obi Wan talks about The Clone Wars but in the context of that film you don't know what the Clone Wars were. You don't even find out that Darth Vader actually had a "real" name and that it was Anakin Skywalker until Jedi.
So there's a large element of the original film where you watch it as kind of a stand alone film (remember in 1977 it was expected to be a flop and the sequels as we know them were no certainty to get made) and when you finally get around to watching Empire it almost plays out like the story and script was developed off the strength of the events of the previous film rather than developing it from the story/treatment that Lucas had written however many years before... and the story went through so many incarnations I never can tell if he ever had the whole thing planned or if he made it up as he went along. Of course by the time he made the prequels the Clone Wars was a focal point because he had already established that conflict in the first film and i don't think he could have got away with doing the prequels if he hadn't done the Clone Wars could it would have been a massive plot hole and as we know the prequel trilogy is already full of them.
So with Episode 7 there has been so much time elapsed between Jedi and the "present day" that there is going to be a similar narrative to A New Hope where events are eluded to but you don't know much about them because they are not played out on screen. Of course there will be events eluded to that you do know took place because you've seen all the movies ("There are stories about what happened...") but in terms of developing the arcs for Finn, Rey, Poe, Kylo Ren there will be events that can't or won't be shown on screen so I think that Episode 8 will be largely built on the story developed in TFA (its already been reported that Rian Johnson had already seen an early cut or unfinished version of TFA before he started writing his script) and so on for Episode 9. and seeing as they don't have the luxury to make saga films to fill in all the blanks i thibk all the backstory stuff will eventually be covered in books, comics, TV shows etc.