that's cuz blizz never mentioned them and neither did kalimdor before warcraft 3 dude, it's a new continent. besides now that they made the universe relatively large they can't come up with some other random race just like that, bcuz it's highly implausible for 2 hidden races to exist for 1111111111 million years and not know each other (elves and "new" race). I'm not saying it's a bad thing, it would be sweet if they added a new race, but the only capital city, could reside in outland. besides the place where the capital city for the night elves is wasn't even accesible in normal wow.