I really liked Ben Mendelsohn's portrayal in Rogue One. I figured this was going to be a cameo, but it seems like he'll be pretty integral.

This is my favorite kind of Star Wars, though. You only get a little taste of it in the original trilogy, but it's obvious there's a bunch of military brass trying to do the-trains-run-on-time fascism post-Clone Wars, but you have this weird Space Wizard wasting budgets on super weapons while his trash can cyborg of an enforcer lingers around their meetings and offers one-liners shitting on their strategies that they have to entertain or else he'll choke someone and no one is sure if they actually have to put up with him or not.