Someday..

Crygil on the future inclusion on Uldum, Grim Batol, and Gilneas:

Crygil Blue Poster

# 18 - Gilneas, Greymane Wall, Uldum, Grim Batol? - June 12, 2009, 7:09 pm Q u o t e: When? Old world needs some love. I'm sure we'll visit these locations someday. Until then, we can only enjoy the wonderful assortment of gameplay we currently have.

I believe this is a significant confirmation that these zones haven't been abandoned entirely.

[Edit]

There's also a thread of several blues once again hinting at these zones here.