So I had a shower thought: what if the next expansion is once again an AU like Draenor, but the reversal of Azeroth?
All the good guys are bad guys, and all the bad guys are good guys. This lets us see characters we normally don't see, and its all in the named of a "different timeline" like WOD.
Arthas was never corrupted and defeated the Lich King Tirion Fordring and Deathbringer Taelon.
Garrosh fights the Barbarian King Varian.
Illidan....was a good guy then became a legion general.
Azshara is killed after holding back legion invasions for 10,000 years.
Kil'jaaden the Redeemer and Archimonde the Purifier are fighting Velen the Doomsayer.