It's not present in all the nations, but Taraboners have varying skin and hair shades, and Saldaeans do as well, just off the top of my head.
Even though Andoran royalty is mostly fair-skinned, they all descend from Ishara, who was dark-skinned and black-haired.
Tinkers are kind of a motley...
I think it's more along the lines of how Robert Jordan described everyone. Nations had certain characteristics, but outliers were more common than if they were set "races."
Traveling the world to better understand my favorite book series....
I'm totally not jealous. :look
Also, thanks for posting that, Jeffan Sedai! :hug I recently got a Twitter account, so I could follow WoTWednesdays, but I don't have an Instagram. :lol