They largely explain things that, as far as I'm concerned, didn't need explaining. As you probably know, they wrote a 2 book conclusion to the series. These 2 books largely tie the Frank Herbert Dune universe with the B. Herbert/K. Anderson Dune universe. And that seemed quite forced to me and, cynically, felt like an attempt to force you to read their Dune prequel trilogy (because otherwise, you'll be WTF is Erasmus?) I feel like Frank Herbert, being an immensely better writer, would have been able to conclude the series without forcing a prequel trilogy onto readers.
It wasn't until I read some of the more immediate books (universe time-wise) from the duo that I came to appreciate how effortless Frank Herbert's writing is. Gurney Halleck is loyal, he just is. And that loyalty is clearly based on respect for the Duke, being on the side of "good", and a hate for the Harkonnen. We don't need a justification for Halleck's devotion. It's pure and effortless character development. The duo doesn't have that seem ease of writing, so instead we get the back story, torture and rape (lazy themes) that tainted the character/original work.
People think that if the author doesn't know everything about the world, it's not "fleshed out". But if you look to some of the best fiction out there, the world is more suggested than built.
I think a good example of this is George Lucas. He went from good to bad by doing the thing people perceived as good. In the original Star Wars trilogy, things just are. The Clone Wars were a line. A throwaway to explain why Leia was seeking out Obi-Wan never having even seen the man. Han and all of his pre-trilogy relationships are given surface level explanations. You never go deep. What happens between A New Hope and Empire is suggested, alluded to, but never explained. And why should they be explained? All the characters know these things. There's no need to exposit these things again. You're given the impression that there exists a much larger world than the small window you've seen.
Then, in the prequel trilogy, everything is presented as backstory to some other element. Stormtroopers are the successors of the Clone Troopers who are cloned from Jango Fett who had a clone made of himself he named Boba. Of course, Jango is also a bounty hunter. Anakin is from Tatooine. Chewbacca rolled with Yoda back in the day. We know, biologically, exactly what allows people to access the Force. And on and on. Everything is given an explanation. And that, ironically, makes the world feel a lot smaller.
I really like the Frank Herbert books. They are on my favorites shelf. The sequel/prequel books were just ok, and felt like they were trying to fill in details that were left to the reader by Frank Herbert. By filling in the details, I'm sure the thought was we are completing the story... but that story was already told.
I slogged my way through the first couple of his son's work, but I read the first page of Butlerian Jihad and, for the first time in my life, threw the book against the wall and tossed it in the garbage.
Inside his pyramid-shaped vessel, the cymek general
Agamemnon led the attack. Logical thinking machines
did not care about glory or revenge. But Agamemnon
certainly did. Fully alert inside his preservation
cannister, his human brain watched the plans unfold.
Given that, a book that would cover the Jihad would probably be another philosophical treatise in the vein of God-Emperor of Dune.
Lower quality writing, and not thoughtful, and the story arc they take things in seems much cruder than what Frank Herbert would have had in mind.
Consider Variable Star by Spider Robinson which is based on 7 surviving pages of 8 pages of notes written in 1955 by Robert A. Heinlein.
http://www.spiderrobinson.com/reilly.html
> So I went home, and received a copy of Robert’s outline and notes, and loved them, and wrote two sample chapters and a proposal and a title (Robert had put down seven possible titles, but even he didn’t like any of them much), and they were all approved by Art Dula, and in the fullness of time the book, to be known as “ROBERT A. HEINLEIN’S VARIABLE STAR by Spider Robinson,” sold to Tor for the proverbial six figures.
> Since then, little dividends of joy keep coming in, like the receding ripples of pleasure that accompany a truly great orgasm--and sometimes, if you’re lucky, signal that it’s about to become a multiple. For example, Art Dula moved me to tears by sending me, out of the blue, Robert’s desk dictionary, heavily used and carefully repaired--Robert Heinlein’s personal box of words. He filled out the package with a pound of authentic Jamaica Blue Mountain. Similarly, sweet Amy sent me a set of her grandfather’s cufflinks to wear as I type VARIABLE STAR, and Jeanne a few pieces of her grandmother’s jewelry to wear for me when I stumble from the typewriter. I feel supported and encouraged by the whole Heinlein family and legacy. That makes me the luckiest writer alive. And one of the luckiest readers.
When writing it, he had the same "these are the words that you are to use while writing as Heinlein."
One of the reviews http://www.spiderrobinson.com/variablefans.html
> This novel should be the example held forth when writers collaborate. Spider has perfectly captured the pacing, feel and stature of a Robert Heinlein story while retaining his own identity. It doesn’t feel like someone trying to “write like Heinlein”, but like someone who’s read every book the man’s written so many times it’s second nature.
https://bookshop.org/p/books/variable-star-robert-a-heinlein...
> "Completing a book from notes by a dead author is almost always a mistake. But Robert A. Heinlein apparently isn't really dead. He was obviously standing at the side of Spider Robinson as he wrote this book, guiding his hand. Variable Star will delight the fans of the greatest science fiction writer who ever lived, and at the same time, stays true to Spider's passionate themes of optimism, kindness, and humanity's future among the stars." --John Varley, Hugo and Nebula Award-winning author of The Persistence of Vision and Steel Beach
This is the way to do continuations - not fan fiction but, for lack of a better word, channeling the spirit of the original author so that you can become them and use the same style rather than imposing your own style on top of their world.
However in Tolkien's case, there was an explicit father son work relationship that was grounded in their mutual love and family life, and the fact that both had similar education, etc.
My understanding is Brian Herbert was estranged from his father and they had a bad relationship.
And Brian Herbert brought in an outside writer (Kevin J Anderson) to do a lot (most?) of the actual writing.
The world of Dune fans would have been better served if Herbert had simply published his father's notes, maybe with some annotations or reflections.
Given the above, and as hasn't provided those notes and documents he apparently found, and as the plot veers quite a bit in tone from what Frank Herbert seemed to me to have in mind, I actually have a hard time believing the notes he is apparently working from actually exist.
Further, the published works he has created are really not good.
At a surface level, yes.
At a deeper level, the authors of the Encyclopedia themselves exist as researchers in the Dune universe, and can be mistaken about their findings. :)