Root was a bad word what I meant was portrayal. Which you absolutely can do, maybe not thier original purpose. But you can make them savage etc.
Yes the Forsaken are definitely partly routed in a Lorderon. The Deathguard use Lorderon equipment, they quite literally live in the ruins of their former lives and consider themselves Lorderonian. They are the true natives of Lorderon dead or not. It's an absolutely a flavour of their lore.
Both are races being nearly totally expelled from their homelands. (And I really don't mind ethier. Both races were stagnant in purpose ATM so maybe this will give them new opportunities to create new lore)