Gnomeregan is interesting...but I doubt it'll be a player city. It would be more interesting to retake it, and then have it utterly destroyed during the Cataclysm.
I say that because neither faction needs a new city, both already have at least 1 dead city. Blizzard is also been verbal of late, regarding player housing, and trying to keep player cities full of life. When both factions already have one dead city it would be silly to toss another in the mix.