i think that Vrykul being their ancestors kinda overshadows them. Just like how Night Elves over shadows High Elves.
And one thing I've noticed is that ruins, or very old settlements are digsites. I have yet to a Tauren ruins, especially since most of their buildings are made of wood and other perishable things. Qiragi architect as far as I know is only in Southern Silithid, those hives all over are just that, hives. So I really doubt we'll see a new race added this expansion, unless they make up another fossil like type that doesnt require ruins(harpies, kobalds, Quilboars, etc)