Yoshida mentioned something in his convo (after visting event room) ...

[Riardon]

Viera were considered for Heavensward, but ended up cut because they decided that they looked too much like humans.

That was back when au ra were a lot more draconic/demonic.

Although some people will say this design is better I would have to disagree. Here AuRa look like mobs out of a dungeon and nothing more. They simply wouldn't fit as a playable race like that. As for Viera well I don't like them except if they make them really different than Miqote. I know some people will say that AuRa are like Miqote with scales but I don't agree. They have some design features that differentiate them from Miqote. You can really tell from far who is AuRa and who is not. If Viera can be really different then it's ok. I personally don't want more races in game. We have enough now and AuRa are still not blended well in game's storyline and Lore. Yoshi's office room clearly mentioned Doomtrain. I think that's the next new Primal and not Thordan EX. Thordan EX will come but it's not counting as a new primal.