This request is almost certainly easier said than done.

Seeing as Viera and Hrothgar are very likely the last races to be added to the game due to how difficult it is to implement any more brand new races and features, with all their animations and armor graphics, I have a simpler solution, I feel.

Ever since Heavensward, we've known the NPC Hilde, and people have clamored for mixed-race character options. To a lesser extent this was also the case with several high-profile Garleans that had Hyur heads, but Elezen bodies and animation sets. Hilde herself is merely a Hyur model with Elezen-styled ears. The Lupin are just Hyur with bestial features and faces.

Rather than add any new races with completely new physiques and voice lines and so on, perhaps it would be a significantly smaller workload to implement some level of modular customization for certain mixed-race combinations. Some would be incompatible, of course, like perhaps a Hrothgar/Lalafell lineage would be too complicated to make happen, but it could be canonically or naturally explained away by them just being slightly too genetically distinct to be viable?

Perhaps that's too discriminatory, I'm not sure.

Again, this is all likely far more easily said than actually done, but what brought this up for me is that I personally love the male Viera animation set and physical proportions, but would prefer to use my headgear. Since I can't just hide my ears to make a helmet fit, and helms and hats are already made with Hyur/Miqote/Elezen/Lalafell/Roegadyn in mind, simply hiding the ears or having a different race's head entirely would sufficiently solve that problem.