I do think that Viera can still and will be integrated into the game if not for 4.0 maybe for 5.0.
Vieras are a seclutive race living in secrecy so meeting them would be really hard.

I do hope that SE will remember what they did by introducing the Au Ra in the game.
Something mi-human mi-animal ? = Miqo'te (Cats)
Something mi-human mi-animal ? = Au Ra (Lizards)

Saying that Au Ra is different because reptilian and not animal is bullshit.
Reptilian or Feline is a precision on the family tree of the race but the main source is still : animal.
So if 2 animals races has been integrated in the game why not more ? Besides the concept of Vieras is already done, plus there is a MALE version, something that others FF never had.