I understand that many hats are difficult to work for Viera because of the long upwards ears that sit on top of the head... and Hrothgar due to the weird facial shape. But that's defnitely not the case with a number of items.
Hoods, for example, they are pretty much flat on top, to the point that some even work for Viera:

And if you look closely, they literally just let the ears clip through, there aren't actual holes or anything, and it doesn't look bad.
This same effect, which appears to be a mesh visibility toggle, could easily happen in - many - older items as well, such as:
This example, however is nighly impossible to be adapted:

The Viera ears' base would clip through the hat's edge no matter how you positioned it, and adding holes to this hat would make it extremely weird, as it's a tiny tophat.
Point is (in Viera's case) even knowing there a lot of hats would be impossible to workaround the ears, there are still a good portion of items that can potentially work with little effort.
My take also is, if they had to choose, I suppose they could make at least the Job artifact armor work, since those are basically the most iconic items we get to have ingame.