How Would Viera Fit In XIVs lore?

[Shurrikhan]

Because the race is more than cat ears.

Hasn't one of the consistently stated concerns been that many don't trust a race not originally settled into the gameworld, and therefore allotted for in world-lore across all content, to be "more than just cat ears"?

This issue plagues any later-added race, but SE really kicked player trust in the gut with Au'ra, when the only excuse for the race was a single Ruby Sea native leading an otherwise entirely Hyuran group of Domans to refuge in Eorzea. Not to mention the difference between the concept art and the actual player models, and the yet continued clipping issues with additional racial features (as with tails, horns).