They may not ever add new hairstyles. SO I wouldn't get your hopes up.

Functionally, Hrothgar hairstyles work the same as Au Ra horns. They use the same variable slot.
This is likely why the hair can't be hidden under helmets as well, just like Au Ra horns always stick through helmets.
The hair system has been utilized for fur patterns and colours, so we're more likely to get more fur patterns.
This makes Hrothgar the only race who can change their skin tone at the Aesthetician.