As much as I like Frank Herbert, and enjoy almost every Dune book, the House series of Prequels were better than Herberts books after Children of Dune.
Absolutely not. God Emperor of Dune
is an intellectual piece of science-fiction literature by a highly articulate, skilled writer that was pushing the genre as far as it could go.
The prequels are pulpy, throwaway Star Wars
action novels. I commend Christopher Tolkien and the Tolkien Estate for resisting the temptation to licence out Middle Earth to other writers. You just end up with a diluted legacy from hack writers looking to score a quick buck.