I've noticed a difference between British v USA sci-fi since the 1980s & 1990s, in that the perspective of rebels versus empire is much more prevalent in England (Blakes 7) whereas USA sci-fi (Star Trek, Stargate, etc) generally the perspective is from the military/empire/centre of power.
Firefly/Serenity tried to flirt with the rebels v empire theme, but it didn't really get that political and then got cancelled anyway. They were more smugglers trying to earn a living rather than guerillas/terrorists blowing up government installations in cause of liberty.
So if a DUNE remake was greenlit, you'd have a sequence of desert-dwelling religious freedom fighters engaged in a systemic sabotage campaign of shutting down spice (oil?) supplies. Unless the screenplay writers just de-emphasised that, like Firefly did.
I'm a big fan of Dune, but if I re-read it now, I couldn't help associating the Fremen with the Mujahideen.
The case of Avatar is an interesting one, as there's considerable overlap with Dune. Religious natives having their lands exploited for their resources, a dude going native and leading them to overthrow the empire. However there was no sabotage campaign - which would have undermined the simple black v white morality (actually pink skin v blue skin). The 'message' of ecological stewardship was prevalent.
Only in the very beginning, when Jake first arrived on Pandora, did you see arrows in a giant truck's wheels - the only subtle hint of a concerted resistance.
Since the Soviet Union collapsed, and there's only one superpower, I don't think movies like Rambo III would be possible today.