Movie seems like a bad medium for it.
But then again, people go to youtube for politics and philosophy, so maybe not.
God Emperor does suffer from being a lot of dialogue. It's a lot of political/philosophical text, setting up the dominoes that will fall over at the conclusion of the book. Which is fine in book form, as you can spend time with the inner dialogue of the characters, and really flesh out their motivations, rationale for their actions, etc. But in visual medium, that never translates well. The Lynch Dune film actually tried to do this, to include the inner monologuing for the characters, with the narration portions of the movie. And most people consider that aspect of the storytelling to be really bad. And while I love that film, I can't really disagree that it doesn't work that well, as narration over visual medium. Because often, if the inner dialogue is lengthy, you will have uncomfortably long scenes of the actor just....sitting there...doing basically nothing, while they think out their lines. So the workaround would be to shorten those lines...which kind of defeats the purpose of having the inner monologuing in the first place. To give the character time to explain (at least internally) their thought process about something.
I personally think SCIFI did the miniseries pretty well, as having more runtime to spread out the story, did give them more freedom to actually explore, and delve into the stuff going on. To build up the political tensions, and show the decay of the society right before everything goes weird. The tragic destruction of previously sympathetic characters, etc.
I think the right kind of writer and director COULD do God Emperor justice. Because it's hardly like low action, politically deep, and wordy movies are impossible to make. There are plenty of ways you could make it engaging, and tense, etc. But, it's certainly not the easiest way to film something, and it will definitely be less marketable overall.
I mean Shawshank Redemption is a movie that is basically nothing but people talking, while under the control of a tyrannical god king, who ultimately is brought low through the machinations of the subjects under him. And it's considered one of the greatest films of all time. But, while the basic structure is similar, the framing of it, and the context is vastly different. Plus it had a brilliant director, a great screenplay, and fantastic actors on every level.