I dunno why people keep acting like Wrathion has no leadership experience and is some greenhorn who needs to prove that can handle leading people.
The guy has, since infancy and for nearly a decade, been leading the Blacktalon, a world-spanning network of dozens spies and operatives. Your very first introduction to Wrathion is that he is nearly innately able to lead people, right out of the shell. Everyone also seems to repeat this idea that he has no experience leading other dragons, forgetting that
Fahrad was a black dragon who recognized his authority and willingly followed him until the whispers overcame his loyalty. He also has, on three sperate occasions, directed player characters.
Considering that Sabellians
only leadership experience pre-DF is the absolute colossal failure of helping Deathwing (i.e. following orders, not making leadership decisions) settle black dragons in hostile territory in northern Draenor, where nearly all of them were wiped out in the ensuing conflict; and then directing the player character to kill gronn in revenge... I feel like, if anything, Sabellian's leadership experience is really the one in question.