I feel like eventually Viera and Hrothgar will get to change hair and the like, because it's effectively turning their nose up at money from items on the FFXIV Store that have hairstyles, but who knows when it'll happen.

I've also seen it suggested from a development standpoint that the reason Viera can't wear certain headgear is because, specifically in Viera's case, the ears are flagged as a hat, and we can't "wear" two hats at the same time.