Even if they add Viera, they will change certain features like their feets. Yoshida has already said that, because of armour design + time, they want races and gender to be similiar, so the chances of having the Viera as we know and love, will not happen. At best we will get a female Hyur with bunny ears, some fur and different type of nose. Another issue is that they are going to design the genders and races after the most played current races and gender. During 2.0 this was female Miqote and Hyur, hence why the female Miqote and Au Ra look very alike.

Assuming they are going to follow the status quo and SE has shown with FFXIV that they prefer to have one working formula, we will see a :
1. A Hyur with animial parts like Miqote or Au Ra, the females will look like your typical anime highschool girl.
2. Males will look very different from the females, they will be either too tall or have different body shape, like with Au Ra and Roegadyn.
3. If they wear full body armour, unless they have extra parts like tails etc, you will hardly notice the difference during combat.
4. They will play safe and make it look similiar to the current races.

Just before Heavensward was released, SE released some of their artwork and personaly I think, if there was going to be a Viera added to the game, they will look more like this:



then this: