Agreed. I’ve been saying this for a while now.
Another pair I’ve thought would work good is Mok’nathal and Broken, both being survivors of broken worlds.
Having Mok’nathal to go alongside Kul tirans also means we have the progentiors and the half breeds and the main race.
Vrykul > Kul Tiran > Human
Ogre > Mok’nathal > Orc