To be honest a dragon class based on aspects could bring in a new variety of playstyles since the aspect specializations have more potential for a class than a demon hunter which ended up being split into two.
However I too fear that this might end up being just an expansion Power system tied to the zones of the new expansion. If nothing else then there would at least be a plethora of new dragon mounts, and probably even a raise-your-own-dragon chain like the falcosaurs, 8.3 bug and other similar chains that give a pet, toy and mount.