I'm trying to answer without making assumption on the genre of the setting...
So what would you like to see in a new fantasy setting?
I want a static world to explore, with all its regions described at a fair level of details that makes it possible to place an adventure everywhere or add your own details and stuff.
I want good details on powers, organizations, important NPCs, religions and other groups, and their interconnections.
I want consistency with the chosen level of technology and magic: if the world is full of wizards and spells are a common sight, I want this to have consequences on everyday life, otherwise don't fill it with magic.
Concepts of life, death and the afterlife that actually make sense. "There's a community of elves living in heaven" or "a demon prince that surrounds himself with undead" make no sense, because "living" and "undead" make no sense in the afterlife.
What would you like not to see there?
A metaplot.
Placeholders, like the usual asian-hinting, african-hinting and american-hinting continents beyond the seas but unexplored yet. Describe everything that is in this world, or otherwise if the settings represents only a small fraction of the world, just avoid hinting at all, at what is beyond.
Tie-ins to other settings. If I play Forgotten Realms, only Forgotten Realms exists. I don't need a hint that there is a route to Dragonlance.
A counterpart for everything. Just because there's a good XYZ in the setting, there doesn't have to be an evil XYZ. Asymmetry is more fun than symmetry.