Arathi? Holy moley how can they not have a claim to the land when they have the Stromgarde Humans. What right do the Forsaken have to the land then?
Lordaeron? Well the Alliance do have a few Lordaeron refugees here and there and especially would after TBC where many Lordaeron foot soldiers would've been. They have no where near as many people compared to the Forsaken I will grant you, but they still have a right. OR as Kosak summed up - https://twitter.com/DaveKosak/status/298167592093364224