With all these First Ones, some kind of hidden super-realities inside other realities and so on, this is no longer felt by Warcraft. And that's not to mention plot holes like the Jailer's 5-D chess game or Sylvanas' actions and so on. It seems to me that even if you say that it was all a dream or a retcon in some other way, it will only hurt the lore even more, because everyone is tired of retcons.