... bluff? Do you have any idea how much work goes into modeling a new race?
Aside from actually, you know, modeling the character (to include the myriad face options), they have to put every piece of gear on said model to make sure it looks OK. With hundreds if not thousands of new gear pieces being added every expansion, that makes it exponentially more difficult to implement new races as time goes on; one of the main complaints with Hrothgar (and Viera) was the lack of headgear due to this very issue.
The development team's resources are limited. Given rabid fan demand for playable Viera...
Personally I don't agree with the decision to split resources between two races (one would be preferable, and I'd rather see a full Hrothgar in the interest of artistic liberty for the devs) but it is what it is. Retcons aren't the way to go.