I also have a feeling that a decent amount of time is going to pass between 7 and 8, and in that time, Kylo Ren is going to get some of the much needed training to bring out his full potential. Yes, Rey stomped all over Ren, but I can see this becoming a much closer battle over the next two movies.
I've always been a big fan of movies telling just enough to make the singular experience great, but leaving enough hints for people to discuss possible theories until we get answers in the follow up. Granted, that is only if there is a follow up, but Star Wars has a ton of other sources for info and side info compared to what is going on in the big picture.

