And being so force sensitive to not foresee the impending doom and destruction of the Death Star to make a quick run to his personal escape pod? (if he had one?) I guess his focus on Luke and destroying him kept Palpatine from realizing he and Vader were going to be Dead within minutes! So much for "I have foreseen it!" 
I don't disagree. But now that they're continuing the story they have to address and re-examine that "ending". Having an oppressive "overlord" like Palpatine and the Empire has been a consistent theme throughout the existing six movies, so it's reasonable for them to continue that in the upcoming movies.
Ah, but Anakin's/Vader's sacrifice prevented the Emperor from corrupting Luke and using him to do his (the Emperor's) bidding as he had done with Vader, so in that regard it wasn't in vain. In that moment, I'm not convinced Vader was thinking about the Empire at all; he was simply trying to save his son.
Probably. He was convinced he would be victorious, but he wasn't so foolish that he couldn't have a contingency plan in place just in case. And if that's the approach they're going to take with the upcoming movies, it's very likely that contingency plan would be for the Empire to continue with his replacement continuing the work he had done.
This approach could make for more interesting storytelling--this sect has slowly been growing and gaining power over the years, and it's emergence forces Luke to get directly involved again.
If, as was seen in the Prequel Trilogy, the Dark Side could prevent the Jedi from seeing the future clearly, why couldn't the Light Side prevent the Sith from seeing the future clearly? Palpatine/Sidious was arrogant and overly confident, so those traits could have blinded him and kept him from seeing (or acknowledging) that the "future" he saw might not come to pass.that was pretty darn convenient for Luke/Vader wasn't it?
maybe the whole thing is orchestrated to give fans false rumors to keep them off the trail as long as possible
I agree. For an "Empire" that spanned millions of worlds across an entire galaxy, the notion that one, singular battle at Endor could have crippled this establishment is ludicrous. Yes, that's what we were fed at the end of ROTJ, but realistically, it just doesn't wash. Along with a trove of other things that are suspect in this saga. Such as the abysmal number of Clones that were being produced on Kamino to fortify the Republic Army. "Two hundred thousand units are ready, with a million more well on the way." Seems like a large number, but the U.S. in WWII had sixteen million people in the service; an army/navy in the Empire of SW would need TRILLIONS of soldiers to cover the territory held under sway by the Empire. One battle at Endor could hardly have been decisive. I think it was G.L.'s tiredness that brought the saga to a close, and not the defeat of an Empire.
