I think they address stuff like that on the extended universe jess but since they are not going to follow the Star Wars EU it is a whole new ball game to me, just because there are no more sith it does not mean that there can't be people that can be influenced by palpatine's and vader's ways and decide to find scrolls or hollocubes or whatnot that allows them to learn at least the basics of what the sith order is and make up the rest as he goes just like Luke did, yes he is NOT a Jedi Knight perse, to me he is a new type of knight that will do the best he can to prevent the mistakes that the old order did, IE follow tradition and vague prophesies and maybe try to find a way to teach future Knights a way to use both Light AND Dark versions of the force thus creating a better view of things cause if you think about it to me the old Jedi aside from Obiwan seemed like robots while the sith seemed a lot more human despite of being "evil" perhaps the new generation introduced in this film could tackle this subject? like maybe a few new order Knights turn dark side and the new protagonists alongside Luke try to find a way to turn them back? dunno, there are a lot of ways this movie can go, I just hope the director can get his act together and not make something that is just ....decent.