A lot of the people think that the last two were worse than the ones before, but personally I don’t see the problem with them. Heretics is probably my favorite Dune book, with chapterhouse and god-emperor as close seconds. Anybody else have thoughts?
Also
spoiler
B E E F S W E L L I N G
The original series eventually delves more deeply into why the society and technology is in the state we see it during the books, but it’s a gradual shift. Character focus remains the main theme throughout.
You might enjoy some of the “prequel” books written by his son, Brian, and Kevin J. Anderson (allegedly based… perhaps loosely… on Frank’s unpublished notes). They tend to focus more on the setting as a whole. Personally I’m not a fan of the actual writing, but there’s a ton of lore crammed into them.