World of Warcraft Midnight Expansion Anticipation

Only one month separates us from the release of the new World of Warcraft Expansion titled Midnight. I'm a rather old player (played it back in Vanilla), but only returned recently in The War Within to play regularly thanks to a friend. I'm excited because Midnight is going to be the first expansion in more than a decade that I will experience from the first day.
What will Xal'atath do with her newfound power? Who will the bosses that we will fight in the expansion? I really can't wait!