James Gunn wrote that flat characters are more appropriate to science fiction than rounded characters.
That depends what sort of SF you are talking about - and what medium. Its a huge genre (...given there's a SF sub-genre of every other genre).
Certainly, the "classic SF short story" can be like that - take a mind-blowing fictional science/future society concept, wrap it in in a minimal plot and deliver it in 5000 exposition-heavy words - possibly without even fully resolving the plot. That's arguably where modern SF has its roots - short stories in 1940s magazines - and of course that's
precisely the origin of the original
Foundation trilogy - it was 10 years of 1940s short stories bundled together. It's a format that
works (a) in print and (b) for SF fans - especially for "hard" SF where a lot of exposition is required. It also makes good radio plays (the BBC 'did'
Foundation - amongst other Asimov stuff - as an audio drama years ago - it's bound to be out there on the interwebs somewhere). It can
also work in a TV anthology show - Twilight Zone, Outer Limits, Amazing Stories (...the last incarnation of that is an AppleTV+ show) - and, for my money, the best SF (in the 'near-future society/human effects of technology' class) show on TV in the last decade has been
Black Mirror.
I think the problem comes with taking that sort of short-story, concept-delivery-system SF and trying to spin it out into a feature length story (let alone a long-form 'Game of Thrones in Spaaace' series). That demands a stronger plot and stronger characters.
Denis Villeneuve proved that wrong with “Dune”.
...well, yes, but third time (or 4th if you count Jodorowsky) lucky....
Dune has a much stronger, clearer plot than
Foundation - it's challenging to film in other ways and also has the issue of a huge amount of back-story and world-building detail to convey, but that's all hung on the backbone of a solid "Hero's Journey (subverted)" plot about Paul Atreides, with plenty of chases, battles, heroics, peril and suspense.
The issues with Dune are more "what to cut out" and "how to have people riding on a giant worm without looking silly" - not "how do we give this collection of short stories an actual plot" (or, if you're David Lynch, "how do we make this already fantastic story even weirder and less accessible") - SF Channel even managed to make a fair adaptation on a budget by saying "look, this is basically a Shakespeare tragedy
in spaaacce".
Funnily enough, it has struck me that the Apple version of
Foundation has made it play more like
Dune than
Foundation - they've focussed more on machinations in the imperial court, emphasised it's feudalist nature, added a powerful religious order (in the books, the Foundation set themselves up as a religion at one point, but that was it), thrown prophecy into the mix and given the main-ish protagonist the gift of prescience (...the books had mind control - but to predict the future you Used Science) emphasised Terminus as a hostile wilderness. Heck, they've even added a flipping
spacing guild to the mix.