Which is really strange considering the repetitiveness of the Oblivion Realms has been one of the major complaints about Oblivion from the very beginning. I guess most modders just tend to ignore them altogether.
I recently had this crazy idea about an Oblivion Realm overhaul that replaces the randomized Oblivion worlds with a completely new, open worldspace of about the same size as the original Cyrodiil, possibly even some kind of nightmarish version of roughly the same landscape, which would even make some sense, considering
Spoiler Mankar Camoran's assertion that Tamriel is actually Mehrunes Dagon's daedric realm.
Anyway, every gate would lead to a specific place in this realm, and those associated with the main quest would also lead to more important places than others and involve more extensive quests to close them than others. And maybe sometimes it would not be possible to exit the realm through the same gate it was entered when closing it, so the player would have to look for another one in the Oblivion Realm.
Then there would be Daedra Cities and villages the player could visit, and there would also be inhabitants that do not try to kill him on sight, but can be talked to and interacted with just like with the usual NPCs. Of course, there would have to be some explanation for this.
But I'm aware that this will probably never happen. I certainly can't do it, and even if could, I could not do it alone and it would still take a long, long time.