That's because Zeth insisted we adapt this piece of art into Windpeak. I'm honestly glad it never saw fruition, because I'm still attached to this aesthetic and lending it to Ura would have been a loss.
Glad you enjoy it! Maybe you will one day see it in an OoT mod
Given the appropiate time and medium, would you tell me more of what the mod would have been? there's not much I can deduce/know better looking at the leaks and the posts on forums.
And well, certainly the original concept as the crystal chasm looks a lot more gorgeous, I can hardly imagine it as a more grim landscape as for the dark world (because I usually imagined it perpetually dark, with an sky similar to that on some of your concept artworks made specifically for the project)
And yeah, would be awesome to see it on an OoT mod.