After the third expansion, the zone will be split in two with a lava river separating the Northern Barrens and Southern Barrens. A fortified gate and high wall now separates the southern Barrens from Mulgore. The zone will be split into Northern (about the same level range as it is now) and Southern Barrens (levels 30-35). Camp Taurajo will be burnt to the ground by the Alliance, who begin to move into Southern Barrens (no doubt from Northwatch, or perhapsBael Modan), constructing guard towers throughout. Also portions of the southern part of the zone will become lush, thanks to the efforts of druid Naralex; however, the Emerald Nightmare will be pouring out into the zone, causing trouble. Finally, the pirates near Ratchet will be forced out, and Mankrik will find his wife's body.

The lava at The Barrens is, as of the playing of the beta, a non-flyable area, where a player will be dismounted if they try to fly over the lava. There is no indication as to if this is a bug or an intended action, or if this will change for the final release, though it appears to be the former since there is no visible way to escape from the lava other than death and resurrection (and in one YouTube upload, releasing after death makes the player automatically rez in a random spot in Southern Barrens, giving more indication that the no-fly zone is not intended and is rather a bug). There is no reason given as of yet from Blizzard as to why the no-fly zone would be intentional, assuming it is intentional.

The latest images from World of Warcraft the Magazine, show a section of the Barrens as a battlefield between the Horde and the Alliance, with war machines littered on the battlefield, it also shows the Oasis next to the Wailing Caverns north of the Lava rift that cuts the Barrens in two, confirming the Wailing Caverns to be on the Horde side of the Barrens for Cataclysm.

The Barrens are now 2 zones, the place where you think it should be on the map, is in fact wrong. Ratchet is still there, you can stop freaking out now. Otherwise, if you haven't seen this already, enjoy the big changes to the Barrens.

Fly through of the Barrens here