From a review of Steven Erikson's 10-volume series, "The Malazan Book of the Fallen," these sentiments:
Successful fantasy does not require magic swords, or the triumphant overthrow of whatever Evil Dark Lord of Black Shadow Midnight Murk is currently torturing the poor denizens of Happiland. It doesn't even require a subplot involving a teenage boy (or increasingly often, girl) who becomes a Man (or Woman) while on a dire quest to find (or destroy) the Holy Trinket
Give me, instead, the evocation of a rich, complex and yet ultimately unknowable other world, with a compelling suggestion of intricate history and mythology and lore. Give me mystery amid the grand narrative. There's no need to spell it all out; no prefaces, please, elucidating the history of Middle Earth as if to students in a lecture hall. Instead, give me a world in which every sea hides a crumbled Atlantis, every ruin has a tale to tell, every mattock blade is a silent legacy of struggles unknown.
I don't feel compelled by this review to read Erikson any time soon, but I agree strongly that in writing about alternate worlds, this is how it ought to be done.
Two examples of masters of this, whom I've discovered only relatively recently: Richard K Morgan and China Miéville.
I read some crappy SF as a kid — "fantasy," that is, trashy romance novels wearing elfin costumes. Yuk. But that hint of magic, or just plain "other," keeps drawing me back to further explore the genre, most interesting of course when it blurs category lines.
I'm happy to hear that increasingly more writers are getting SF right.