Logan Riddle

(Spoilers ahead) A lot of it feels just thrown together. I know they have much to cover but they left some story arch's with no satisfactory or recognizable endings. And all of a sudden we are to believe the backgrounds of some major characters can change with the blink of an eye? What was the main point of Darth Vader if he was not the one who was suppose to bring the two sides of the force to equal ground. Palpatine even said it then. But now he all of a sudden has a granddaughter that is suppose to do it? Was he lieing to Anakin the whole time?