This is not for the setting of the next games. Rather, this is discussion of Planes of Oblivion which could support an expansion for a future game. Something like the Shivering Isles for an entire world or just a place you visit like Apocrypha. Which planes of Oblivion would work well in this format. We've already seen places like the Deadlands, the Shivering Isles, Coldharbour and Apocrypha in great detail, but which plans would be interesting to visit?

Hircine's Hunting Grounds seems like an interesting place to visit, with Skyrim teasing the "Harrowing of the Hunting Grounds" and all. Would be an interesting expansion, going to the Hunting Grounds. The Realm of Boethia seems also very interesting, with hedge mazes and twisting towers. But out of all the realms, I think Clavicus Vile's Realm would support a Shivering Isles-like expansion best, since the Inferal City - Umbriel was part of Clavicus Vile's Realm. Clavicus Vile seems like an interesting Daedric Prince, one that cold rule a realm like Sheogorath did in Shivering Isles. Quagmire seems like a realm you could visit kind of like Apocrypha, needing to enter the realm to recover dreams and therefore knowledge.

We have already been to Hircine's realm in Bloodmoon.

Alrigh, how about revisit? The Harrowing of the Hunting Grounds would still be interesting.