Originally Posted by
Iscah
I don't think it's anything to do with specific system limitations, but the fundamental design of how characters are assembled. Whatever trickery they had to do to implement their vision of Viera and Hrothgar, it involved sacrificing the ability to equip hats as normal – and judging from what does and doesn't work, specifically sacrificing the ability to split the hairstyle into upper and lower halves.
If it is something inextricably linked to the design, they may not be able to fix it at all, or not without altering some visible part of the character appearance.
If they can't overcome that specific issue and don't want to forcibly alter everyone's existing character to fix it, then for the time being until and unless (and if it's realistically possible for them to implement) a full rework of the character design system, this type of headwear may never be able to work at a technical level that no amount of "it's a special hat that everyone deserves equally" can overcome.
Maybe they'll find a solution to the hair issues and then we'll see a flood of hats working normally. But until we see at least one, any expectation of whether a hat works or not is entirely down to its design and not its origin.