just watched dune part two, and i gotta tell ya, after being blown away by the scope and promise of dune part one, part two seemed a rushed and jumbled mess to me.
i know i'm in the vast minority on this, but part two of course, could have, and should have been expanded into at least two or three separate movies to do the story justice. the majesty of the first movie was mashed into a frenetic eye rolling dash to the finish with nothing happening that should have hit me, with the same tingles up my spine, as when i read it all those decades ago. not one scene or event made me feel anything.
but wait a second did them just defeat the entire galactic empire in the span of 90 seconds. boy that was convenient huh. blech,
i did not like it at all. imma rewatch at 2160 when i can, and maybe come back to edit, but i kept waiting for the cool shyt to start, and they blew on past all the cool shyt for 2 hrs and 45 minutes.
the whole thing was nothin but a dust storm.
Others have answered partially his purpose, but the Baron's plan was for Raban to exploit and crush Arrakis as much as possible to recover the funds spent on the invasion, then the na-Baron comes in as a benevolent saviour for the people. The Harkonnens get a bunch of money, control of the spice, and a cushy job for the Baron's favourite
How would a complete psychopath who has been waging war against a people come in as its savior? That doesn't make sense to me.
It's different in the books shrug
I think the first time Feud-Rautha comes to Arrakis in the book is with the emperor and Baron and those guys right at the end. No-one on the planet knows of him yet