My friends and I are already planning on starting up a Horde campaign, but we're going to wait at least until the Manual of Monsters is released so that I'll have some Warcraft-style monsters to throw at the PCs.
One of the PCs also wants to play as a troll, so hopefully the stats for troll PCs will be in the Manual of Monsters just like how the 3.5e MM includes stats for several monsters that tell you how to play them as PCs. If that isn't the case, though, we might not be starting our campaign until December, when the Alliance and Horde Compendium comes out with troll PC stats.