The Horde getting a Dwarven variant isn’t not a sign to me that faction exclusive races are done. For example, there are signs that the Broken of Argus will be rejoining their Draenei kin, and since the Man’ari were quick to become a customization option, the whole thing with the Broken feels more like seeding for a playable race. Granted I could be wrong, but in the event I’m right, it’s important to note there has been nothing done to seed the idea of Horde playable Broken.
Furthermore I can see Midnight having playable Forest Trolls and I just really can’t image Forest Trolls on the Alliance.