We have been on a quest to find "The Next Tolkien™." There's always someone being called "The Next Tolkien." Various names have been tossed out throughout the years: Terry Brooks, Brandon Sanderson, Robert Jordan. I think we're all looking in the wrong place: we're looking at the various "high fantasy" types, when in reality, the next Tolkien was more important than that.
I nominate Iain M. Banks.
Tolkien wrote that his had their own internal logic, that his fairy lands were to be taken seriously on their own merit, and that their real purpose was to transport the reader far and away from the current world to a different place, a place where we encountered new and powerful visions, ones at the end of which we come out, having encountered dragons and demons, and we see our own world in a new and different light, somehow enchanted, yet with a new commission to make it all better, to keep it running, to thrive.
You can't read the Culture as a series without having an experience as powerful, as fundamental, and as valid, as reading about Middle Earth. More importantly, as science fiction, The Culture is a call to action that Tolkien was sadly missing from The Lord of the Rings.
Most Culture novels have amazing payoffs at the end, huge set-piece scenes (each distinct and unique, so not entirely like the "money shot" of porn, a David Weber novel, or a Transformers movie) that happen in such a rush, and often with great redemption in the face of utter ruin, that are exemplars of Tolkien's eucatastrophe, a "fantastic upsetting" that sets the world right again. Unlike Tolkien's work, Banks never proposed that there was a hierarchal structure to reality itself that causes some to "rightly order their lives," working together to create a universe "hospitable to humans." Banks's call to action was to ask us to do it, to pick up more than just the axe or the plow, but to work to make the universe a better place.
Tolkien said we should take Faërie seriously. Iain M. Banks told us that not only should we take Faërie seriously, but that it was our moral duty to build it, because no one else was going to help.