Mordor without Sauron?

[Manwe Sulimo]

Well, Gorgoroth probably stayed really uninhabitable, smelly, and dark.

Nurn, on the other hand, had to be a bit fertile. Elessar gave Nurn to the slaves in Mordor, and I don't think he would've given land similar to Gorgoroth to a group of recently freed slaves. I expect that Nurn was (since it was on the inland sea) comparable to Lebennin (of course not as fertile, since it borders Gorgoroth, but comparable. Or maybe to Egypt on the Nile).

I doubt that Morgul Vale healed for a long time, but that it did eventually. The Elves moved in to Ithilien, and they do wonders on formerly-foul lands (South Mirkwood/East Lórien, anyone?).

Gorgoroth never would be redeemed...it's like Ard-galen after the Battle of Sudden Flame.