More was put into the Vulpera than any of the allied races so far, except Kul Tirans. Every other race has mostly just been a relatively slight modification to an existing race, while the Vulpera actually have different faces, an entire tail, way more skin colors, etc.
While there have been NPCs that can wear player armor in the past, they have never had this much customization or uniqueness from other races because it was never necessary. They're absolutely going to be a new race.