As we all know, there's a whole huge vast pile of books detailing exactly what happened after the end of 'Return of the Jedi' in the Star Wars universe. But let's face it--they were all written before Lucas redefined the terms of the game with the prequels, and a lot of the assumptions they made about the series have turned out to be wrong. (Just try reading Timothy Zahn's "Thrawn Trilogy" now, in light of what we've learned about the Clone Wars. Attempting to reconcile the two will destroy your brain.)
So let's think for a moment about what we might see in a post-'Jedi' universe now that we know everything. It all revolves around Luke...and I don't think he's destined for a happy life.
Think about it. In addition to seeing the ghost of his dead mentor, a ghost only he can see, he's now apparently being followed around by the ghost of Yoda and the departed spirit of his father. And Yoda, well, he's gotta be bitter. Luke basically took his whole philosophy of the Light Side/Dark Side dichotomy and jammed it into a toilet and gave it a swirlie; he's going to have to reprioritize his entire philosophy, and that's something that's very hard to do when you're a) 800-plus, and b) dead. Yoda's probably just going to sit there bitching at Anakin all the livelong day, stopping only to scream at Luke for training Jedi wrong.
Meanwhile, Anakin and Obi-Wan will be having their own problems. Anakin was never very likeable--smug, whiny bastard, really, and being the only one of the three who's mastered the "blue ghost" technique well enough to get a young, handsome ghost body won't help--and there's bound to be a lot of bickering there. And from Anakin's point of view, the same two schmucks who trained him so well that he wound up falling under the sway of the Dark Lord of the Sith for decades are now giving great advice to his son, too. That's going to go over real well.
Then there are the other ghosts. Oh, sure, we didn't see them--but we've learned that this is a new technique that Qui-Gon learned. At the very least, Qui-Gon should be wandering along soon, and we know he never got along with anyone on the Jedi Council. At worst...well, imagine Luke screaming "Shut up! SHUT UP!" at thin air while to his eyes, hundreds of Jedi push at each other to tell him best how to re-establish the Jedi Order. Sure, he's a respected military hero (despite spending several months effectively AWOL over the course of 'Empire'), but how long before he's committed to a sanitarium "for his own good"?
That's the ultimate death of the Jedi order. Not extermination at the hands of the Sith, but Luke, straitjacketed in a forgotten institution somewhere in the Outer Rim, begging Mace Windu to stop yelling at his dad for the whole hand thing.
Then they start in on Leia...