Feb 4th 2011 11:49AM Southern Barrens was probably the most unexpectedly enjoyable zone. There's nothing flashy going on, but it might contain the most compelling scene of Horde vs Alliance conflict in the game.
Another chain that nobody has yet to mention is the entire Eastern Plaguelands experience, revolving around the caravan. It was an excellent device to (pardon the pun) drive the player through the zone, and contained some enjoyable new characters as well as old favorites. Though Arathi and Hinterlands are abominable, anyone leveling an Undead alt should carry through to Western and Eastern Plaguelands.
I'd also have to agree that none of the new zones really felt as "epic" as the best of the revamped content.