A writer actively submitting stories to market might spend a lot of time wondering what editors want. I just came across this lovely group interview on Clarkesworld, grilling a bunch of Science Fiction, Fantasy, and Horror editors on just that topic.
The story’s almost six years old, but it’s not that much out of date. Gordon Van Gelder isn’t editing S&SF anymore, for example (though he’s still the publisher and owner). Fantasy Magazine is now merged with Lightspeed. Jim Baen’s Universe is defunct, and so is Weird Tales. But most of the editors are still powerhouses in the field, and their answers are fascinating.