Warchief is going to become more of a 2ndary position, the person who is warchief will be in charge of the horde's military affairs.
But, there's going to be a new position created to be the "leader" of the horde. (think president/prime minister)
My proof? Cannot disclose.
Though sit and think about it for a second and think of the theme of this expansion.
Lor'themar Theron will also be the warchief of the Horde.
So yea everyone who doesn't like this idea, yes it's happening, but it's not the same warchief position persay.
Think back to the landfall questline where lor'themar says "I'm not a politician, I'm a ranger" biggest hint in game currently. You'll see more play out come next patch.
Though I will say the leadership position of the horde is unknown at least to me. But Lor'themar WILL 100% be the next WARCHIEF.
If you're gonna flame and cry about sources, go ahead and book mark this page, and I'll see you in a few months.