Earlier quoted context omitted.
The biggest flaw with the sequels is that they end up not ending- in the same way the Dune Messiah was a setup for Children of Dune, it seems that Heretics and Chapterhouse were leading up to the seventh book that Herbert died before writing.
His son Brian and Kevin J Anderson did write the last installment based on detailed notes from Frank Herbert, so at least the story is complete. While their writing is not as brilliant as Frank Herbert's, the books they wrote, mainly the prequels, have helped me understand just how big the original vision was and have helped me enjoy the sequels more. God Emperor is truly as masterpiece, but it took a couple of reads…
The same way KJA "improved" Star Wars.
His wife, incidentally the editor-in-chief of the publishing imprint that then owned the publishing rights to the Star Wars and Dune literary universes, is to blame for unleashing his word vomit on mankind.