Since now we have the Gauntlet and Whispering Dunes branching off from Scallop Shores, a Hunter occupied place, and a lot of people complain about not having enough mid-level (20-30) content, I propose a place called Blackmoon depths so be created at Enchanted Forest, near the Tree of Life.
The place would be outside the Tree of Life entrance, and would be something like a pit/tunnel leading underground. Some mage camp could be set up (stone walls with vines? anyone? Hogwarts feel?) No “gauntlet-ish” place would be needed and would lead straight to the area.
There would be a lot of stagilmites on top of the Blackmoon depths and would look like a giant cave overall.
Some black slimes, snakes and fishes in lakes inside the depths. I don’t really know how they would work. Make their level range 25-30 though.