Metzen’s original pitch for the expansions after Dragonflight before Blizzard made him split it into 3 and shoot lower content-wise

Expansion 1 (11.0-11.3)
>Void invasion of Azeroth led by Xal’atath
>Alliance allied races throughout the expansion: Earthen, Arathi, Ethereal, High Elf
>Horde allied races throughout the expansion: Haranir, Ascended, Undermine Goblin, Amani Troll
>Zones throughout the expansion: Tel Abim (instead of the Isle of Dorn), Ringing Depths, Undermine, K’aresh, Voidstorm, Twilight Realm, Ahn’kahet, Rootlands
>Delves

Expansion 2 (12.0-12.3)
>Titans attack Azeroth after the heart is corrupted by Xal’atath
>Constellar race
>Astrologian class (2 specs)
>Artificer class (2 specs)
>Zones throughout the expansion: Storm Peaks, Lordaeron, Grizzly Hills, Quel’thalas, Howling Fjord, Zul’Aman, Zul’Drak, Arathor, Avaloren
>Player housing
>Guild halls