Funny thing about a story, nobody wants to read or watch or listen to it when you talk about the Johnson's next door who haven't really done anything of note in their lives. What people want to hear about is the ones who make the big impacts in the world, whether it has to do with social media, politics, military, or anything else.
Plus, the Star Wars Franchise is about familiarity and the story line, not the world the story takes place in. Typical fans want more of the story, not new stories that are unrelated. Only the really dedicated fans give a ---steaming pile of meadow muffin--- about the universe Lucas created.
I happen to be a big fan, but I also understand that you can't market something the majority of your audience doesn't care about. My favorite part of ep 7 is how most characters thought the heroes of 4-6 were just a myth, a story told by mom or dad before bedtime, and I like how they had no connection or knowledge of those heroes. And I can't say I wouldn't love to see new stories in the same universe that don't involve Jedi Knights, lightsabers, and heroes from past movies, but when a movie comes out that continues (or fills in) the existing story, I still want to go see it. When you add to a story you need to have some strong connections to the characters in the story.
Look at it this way: Rogue One is about the first spies who stole the plans to the death star. Vader was involved in the death star, possibly from the start. How can you not have Vader in a movie about the space station he was using to keep the galaxy in line without at least a cameo?
BTW, it was the second death star that Bothans died to get the details on. Not the first.