I think that Blizz should address the other side of Azeroth. I like the idea of the way the cosmological forces are being written, but we could also have a whole new opportunities on the other side. Something like a proto-Azeroth, where the Keepers created proto-types and would later be perfected on Kalimdor (Blizz can easily add something like this, just look at Void Elves). For example, we can see a race that is the missing link between Trolls and Elves, or Humans and Vrykul. We can also have intelligent/evolved version of races that are considered a bit dumb by us: Gnolls, Yetis (I imagine their evolved versions looking like the Qunari from Dragon Age) or even completely new races, like a humanoid T-Rex. For the story, we can have it explained that the other side was hidden ina realm similar to the Elemental Planes, and something happens that connects us.
What do you think?