I'm setting myself up for abuse simply by writing this, but I've just finished reading the Dune series of books, and I found the ending to be a real let-down.
I suspect a good number of people have read the original book by Frank Herbert, which typically gets universal acclaim, and indeed made it onto the 100 Greatest Novels by the BBC. Its a great book, that takes on and deals with vast subjects...not only the story of the people it involved, but of their families, the politics, religion and nature of the universe, as well as a huge amount of detail on the world itself.
Frank Herbert went on to write a long series carrying on after Dune, and its here that he lost a lot of readers. While Dune itself was focused on the planet, future books in the series become more and more about people with strange powers, and huge upheaval of the human race. I personally enjoyed them...they had an epic feel to them, and while the subject matter was sometimes a bit cranky (and it gets really strange once you reach God-Emporer of Dune) it painted the world very well. Even later in the series there is a shift in focus to the Bene Gesserit (which is effectively a military knitting circle). The series covers thousands of years in total, though it carries through certain characters and themes, and focuses on certain time periods very heavily. As with many old-school sci-fi authors, the underlying themes are very much based on society, and how it copes with situations.
Frank Herbert had the indecency to die in 1986, leaving the series incomplete (the last book he wrote being the 6th, Chapterhouse:Dune). It's very much a cliffhanger, with an ongoing theme of a huge, unknown threat being levelled against the entire human species. He had always planned a 7th, and final, book to complete the series, and had completed notes on the book, but just hadn't gotten round to writing it.
At this point in steps Brian Herbert, his son. Together with Kevin J. Anderson (who is probably best known for being a co-writer of the X-Files) he has spent the last 9 years visiting the universe his father created and expanding it/raping the corpse (delete as you feel appropriate). He started by writing a series called the "Prelude to Dune", which covers the history immediately before the original book. With the best will in the world he is not the writer his father was, and the guidance he got from Mr Anderson is obviously less cerebral than Frank Herbert. The end result is a writing style with a bit less delicacy, and less refined. It does read a bit like a screenplay. That said, it dealt with the subject matter fairly well, and for the most part avoided doing a Star Wars Episode 1 by introducing glaring continuity errors ("I don't remember owning any droids"). As someone who has read the original series, it was great to see old characters back, and to revisit the world. I will admit to a small amount of pink-vision. Even at this point, however, the shift from social commentary to character-based plot was already showing through.
Next up came another series, which covered a part of the Dune history with was often referred to, but never fully explained...the Butlerian jihad. Without wishing to spoil the story too much in the Dune universe there are no computers/robots etc, and it is explained several times that "thinking machines" are banned due to a slight Terminator-style issue at some point in the past where they took over. Over the course of three books Brian and Kevin depict this key part in the history of Dune, I suspect without too much attention to his fathers notes. There is some mention in Dune of key families, and their alliegence during this time, however I suspect it didn't include giving the AI Overmind that much personality, or giving him a sidekick. Again, while it didn't do too much in the way of continuity errors, and did meet all the requirements it felt a little over-hammed. Fine in separation to the Dune series, but other than that it didn't blend too well, either stylistically, or content-wise.
So then we come to the most recent two books..."Hunters of Dune" and "Sandworms of Dune". It should have been a giveaway that a story-arc that Frank Herbert planned for one book was eventually published as two. These books represent the culmination of the Dune series, and are allegedly based on Frank Herberts notes for Dune 7. The first one was passable, however the second was bloody awful (and I've really, really been trying to give this leniency upto now). It's full of contrived situations, awful dialog, and horrendous continuity. One of the main issues is that it re-introduces many concepts and characters from the Butlerian Jihad series, and this finally breaks the continuity. There is information suddenly made available that quite literally magics up from nowhere. Several people develop insane abilities from thin air, and it reads in places like badly-produced fan-fiction. Its a crime against the entire series. Its even got a "happily ever after" ending to it where everyone hugs and is best friends, which is never what Dune was about...I mean, God-Emperor was all about how shit a situation like that was for everyone involved! The story covers 14 books in total, over the course of 43 years, and right at the end its screwed up fatally...
I'm quite depressed after finishing it...I can't unread it, and to some extent it's soured Dune for me...perhaps I was better off always wondering what the big threat was, rather than have Brian Herberts sledgehammer of crass pour it into my ear like so much hot tar. He's already announced plans for a new book, a sequel to Dune no less (that fits into the time gap between Dune and Dune Messiah). There is no way that this can be good, as it deals with more core times in the Dune timeline, and will undoubtedly contain huge signposts of contrived plot to link to the later books he's written. There is also a new film in the offing, which they hope to turn into a series. Brian and Kevin are involved, so my hopes are very low...
There is another series of books I've had on the go for a long time ( The Wheel of Time ), where the author has also recently died just before writing the final one. Another author (friend of the family) has picked up the baton, and is currently in the process of completing it, with input from several other sources, and the notes of the author. I desperately want this book to be good, and to do justice to the series (which is massive...11 books of huge weight, and an overarching plot and storyline with insane levels of detail). Robert Jordan was part of a community of authors, and always worked closely with his family and friends, so I'm holding out hope that the spirit and integrity of the series can be maintained to the end.