I wasn't able to turn up any more information about this area, aside from one new daily quest that mentions it, where a Shattered Sun Offensive NPC sends you to the area to collect five "Razorthorn Roots." Sounds like a ground pick-up. The quest is filed under Terokkar Forest, so I'd guess that's where Razorthorn Rise officially resides. Does anyone know anything else about this zone?
Update: Maybe not a new area after all. Still, this is the first I've heard of it.