I think the main thing is that Rey and Kylo will continue to be developed as parallel characters. Ren is really more of anti-Luke Skywalker than another Darth Vader. I think both characters arc's will mirror each other to some extent.
I don't think we will see Luke do much sabre stuff or Force super powers. That was the prequels and the old EU/Legends. TFA went back to basics; the Force was mostly about the mind and spirit and the contest of wills during the two times that Rey and Kylo confronted each other. They brought out the super-powered, telekinesis stuff pretty sparingly and only for dramatic effect, just like the OT. So I think they will continue to be reserved with that sort of thing.
I don't think Luke will fight Ren or save her bacon. I'm glad they didn't do that in TFA and I don't think they will do that here.
I'm leaning more and more towards the camp that Rey is not Luke's daughter. Too obvious and it doesn't really jive with Maz' comment about Luke being her future and her family
being behind her. She clearly has a connection to the other characters, and I think both Leia and Ren know or at least suspect what it is.
I hope we will see the further development of the friendship between Rey, Finn, and Poe. Rey and Poe haven't even met yet and while Finn is good friends (only friends) with both of them they need to be developed into this trilogy's family, just as Luke, Leia, and Han were for the OT.
I think Snap Wexley, Greg Grunenburg's character, is going to be the new Wedge.
I expect we will find out the full details of the fall of Ben Solo/Kylo Ren, the failure of Luke's new Jedi, and what he has been doing all of this time. Did he find the first Jedi temple and if so what did he learn and why did he remain hidden?
I think we will find out all about Rey and who she is and where she comes from.
Artoo and Chewie will probably be in it. The fact that they both went with Rey to see Luke is probably significant. I imagine they writers intend to use those characters. Chewie's role in TFA was the most significant one he's had in any movie. Really liked the moment he had with Rey in the Falcon cockpit at the end.
I'm really curious how much time will pass between the two films. Both Rey and Ren had cliffhangers that imply immediate resolution. We obviously want to see that first dialogue between Rey and Luke, and we want to see what Snoke has to say to Ren in the aftermath of the events of TFA (he's success in killing his father, his failure to defeat Rey).
I think Leia, Chewie, Artoo, and Threepio will survive the new trilogy. I think chances are Luke will not, and he will be killed by Snoke, possibly in a way that mirrors his fathers' sacrifice in Jedi. If this happens I think it will help Kylo Ren turn back to the light, but probably not until IX.
I think we will get some hints as to who Snoke is and where he comes from but he will still remain pretty mysterious.
With Maz it's hard to say either way. She will almost certainly turn up in the Han Solo movie but she has a lot of knowledge about Jedi/Sith lore and the Graflex lightsaber, which is obviously significant to the story given Ren recognizing it and not being surprised that it had been found. However, I suspect she won't appear again in the sequel trilogy, but probably turn up in a lot of other places.
I hope Daisy Ridley is really good at hand stands.
