I don’t think I appreciated God Emperor until after my 4th read through of the series. Frank Herbert definitely has a great insight into the human condition. Soul Catcher and The Godmakers come to mind most readily but his entire body of work explore different facets of humankind.
To be fair to the Dune universe, the reason they used swords was because shields made projectile weapons useless and Lasguns and shields just killed everyone (like a mini-nuke on both sides).