Which the horde, storywise up to BfA, ironically proved unwilling to do. It took yet ANOTHER genocide for them to realize that maybe having a Warchief that speaks for everyone is a terrible idea.
The problem is, again from strictly a story perspective, the alliance has ZERO reason to ever believe the horde is going to change. We’re sorry or We’re different this time looses it’s meaning after the other side continues to revert to being genocidal maniacs every two years