What if the beginning of this expansion the Legion does attack and we are all but utterly defeated?
To me, this would explain why Anduin goes to free Garrosh - desparate times call for desparate measures.
Then, the speculation is correct about going back in time to Draenor. Wrathion sees that we were never prepared for the destruction that is coming and he does go a different route learning about the ability to go back in time to when the Legion first gets to Draenor. Cue the rest of the speculation and the name of the expansion that people have already been theorizing over.
What if World of Warcraft does go back in time and permanently changes (retcons) everything that has happened? After this expansion, they could do anything they want from the point of Warcraft 2 onward, completely diverting from the story that we know from Warcraft 3 and WoW? Even if I am wrong about my next point, this is still possible if this expansion deals heavily with time travel.
Whatever we do in this expansion could permanently change the world in that timeline, while we are left to wonder what happens in the timeline where the legion assaults Azeroth. Until Warcraft 4 comes out.
Warcraft 4 could follow a separate timeline than WoW much like EQL and EQ2, and other games, are the same world but different continuities. It would give us a world that alliances would again be able to be splintered, and it would not necessarily be Horde vs Alliance. Everyone could be represented separately, even the new Lich King and other races that we've come to know in WoW. And all of this would be after all the great heroes (players) have fled back in time and they are left to deal with the Legion without many of their greatest heroes.
What do you think?