True, but the exact opposite of that is also true.
Without a Warchief to keep everyone in check what's stopping the Warsong Clan, Mag'har, Forsaken, Grimtotem, Trolls from doing whatever the fuck they want? They could even resort to fighting among themselves. This is the exact reason the Warchief title was created, to unify the warring Orc Clans and give them a single purpose. What's stopping them from starting a war now? Baine asking them politely to stop?
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As a Horde player I have to say it would be nice for a change. Tyrande and Genn as villains. Anduin can have a Thrall inspired guilt trip and go into exile as well. Let the Alliance have their share of drama and let the Horde rebuild and be the stable factor for a change.