John W. Campbell!!!
The man who singlehandedly took the genre of Science Fiction from silly B.E.M. (Bug Eyed Monsters) to a thinking man’s genre of reflection and consideration. He REJECTED many of the submissions of Asimov and Heinlein (and many of we now consider masters of SF) from what was then “Astounding Science Fiction” (later to be Analog Science Fiction and Fact, edited by The Good Doctor).
By demanding the same literary litmus tests of SF as for other genres (and demanding they exceed other “pulps”), Campbell propelled SF from teen-geek fringe to the mainstream.
There isn’t a single modern SF movie, book or extension that doesn’t owe Campbell for its very existence.
The best example of what a great editor can do with a great writer is “Nightfall.” A short, yet compelling drama. The fact that drama is set in an SF backdrop is almost irrelevant.