I was thinking about this at work and there are some older mmos and RPGs that I think would be fun to explore in WoW.
For me personally, the Planes of Power expansion of EverQuest has a soft spot in my heart and I think it would be so fun in a WoW interpretation.
What would you like as a zone in the game?
The Glowing Sea from Fallout 4.
Extremely dangerous. EXTREMELY dangerous. Like you better have a battle buddy by your side… or else squeal for help with nobody coming (absolute zero success) and you die alone…
The entire Runescape world
Eternal Battlegrounds from GW2 for sure! WvWvW was so much fun and would have servers warring against each other in wow.
I’d love a zone with rapid water erosion like in Paper Beast, the outcome is otherworldly and stunning.
Flowing rivers, but the trajectory of the river is constantly changing! The rest, irregular lattices of sand, rock, and life
Icicle Inn from FF7 (original)
Vex Thal from Everquest. Back in the day it was a huge raid that took several hours to even days to clear. WOW never had a raid of this size.
was it right. went back to gw2 a few days ago. they no longer do server v server so they broke the community and it still mag vs all. its much worse and i played mainly for wvw but yeah would be fun here
A mix of the lands between from Elden Ring and the Arc from the original Halo game.
I remember farming the items to get into Vex Thal was half the journey to even getting in 
Plane of Mischief
Clair Obscur shamelessly ripped off the Erd Tree zone with one of its zones with “The Golden Tree” and it is immensely beautiful, so I think you could probably just do the same thing in WoW.
Lore-wise, a new world tree that went too deep causing it to tap into a vein of Azerite causing it to take on that golden Azerite hue with a faint blue glow could be sick.
A zone like that, but mechanically like the Maw where its very hostile to the player to create this idea of a forbidden or corrupted garden of Eden could be very cool.
A zone like Horizon Zero Dawn’s world would be cool.