I'm just going to say it. The Heir to the Empire Trilogy is what actually happens. There was Return of the Jedi then a vacuum, and the Heir to the Empire trilogy happened and all of a sudden in 1991 Star Wars came back, "Tie Fighter" the videogame in 1994 and then the expansion was all about Thrawn and every piece of media since then has used things and characters from those three books. He added so much more, the most important additions he made are Mara Jade, AT-PTs, Slicing, Interdictor Cruisers, Coruscant, The Jedi Academy at Coruscant, giving wookies claws and the list could go on. Heir to the Empire was the only thing guiding the events after Return of the Jedi for 22 years, you can't just go back now, if you've done anything Star Wars in 22 years you've seen those changes, even things like Battlefront 2 is full additions he made, even the PREQUELS have things he invented in them.
They probably could have made those movies in 1991, but now they really can't. It's too late, but it's what people are expecting now because even without reading them the material has made it's way into the universe, despite all the insane rambling nonsense Lucas put in the prequels(he'd have to cut nearly all of Yoda talking about the force in Empire Strikes Back to make it consistent.)
The only way I can see this new idea working, is if the next movie is a tight political thriller book-ended with action scenes. Something like; Leia is a skilled diplomat trying to keep the 20 year old new republic together during a new crisis they face in the film, Han Solo is focused on keeping supply lines running and espionage , he would have to be an admiral or something(this is problematic, his character arc makes him unlikely to accept a "desk job", more responsibility, yes, but not something that slow, but you just can't have a 71 year old believably running around anymore) Luke following his arc from whiny farm boy into calm, dedicated and concentrated Jedi would more or less become a Yoda figure training other Jedi. The action would have to be carried out by children or apprentices of those main characters.
The only film I can think of at the moment that approximates what I'm talking about is Clear and Present Danger. The story is about Jack Ryan gradually uncovering an illegal war, more or less from his office chair in Washington D.C. but the film is full of action scenes from that illegal war that depend on the story in D.C. to make sense and have weight. The only time Ryan is in an action scene is at the end and even then you get the sense that he just barely makes it out because he has been sitting on that office chair the whole time, I think this type of story could work, but I doubt they will have the self control to use the original characters without making them Crystal Skull all over the screen.
The best thing they could do is let them be old, use them as actors instead of action heroes ala Alec Guinness
