Pre-Event (7.0 patch) - We go back to Azeroth after saving Draenor to find Naga/Demons trying to take over our cities. We team up with heroes of the past (Including Alleria, Turalyon and Illidan) and retake the cities for our own. In the process Vol'Jin disappears (Captured? Missing? I'm not sure).
Turns out the Naga have teamed up with some Old Gods / Demons and are trying to take over Azeroth.
Something happens with Gul'Dan at the Tomb or Sargeras, but not straight away.
Main Baddies are Azshara + Old Gods (1 or 2, unsure). wanting to 'cleanse' Azeroth before the big battle.
Expansion then begins with us going to a new continent (continents?) via boat. Boats play a huge roll here expanding form the shipyard. You can get your own crew, have a guild-wide boat, use your boats in PVP battles, explore many islands etc. Reminded me of Archeage.
There will be a lot of story/lore involving Anduin, Wrathion, Yrel and Illidan. It feels like they are setting Anduin up to be a huge hero in the future. Legendary quest involves Wrathion/Anduin again.
With the return of Illidan there will be a new class added. Unsure of the name, but it looked similar to a 'demon hunter' everyone is talking about. Can use rangedweapons (bow/gun) & melee weapons (sword/fist weapon). 3 Specs. Starts at a higher level (85-90). Hero class?
They are adding 'Subraces'. Including letting Undead choose which race to be undead. Different Dwarven clans, different Orc clans, etc. Didn't catch everything here.
They're adding a new system where the player can change the look of their spells, similar to the shadowbolt glyph. Unsure how exactly this works, possibly like the warlock class quest for green fire, you get more as you progress through the expansion.
They realize how lackluster PVP was in WoD and are making it a larger focus in this expansion. New battlegrounds/Arenas, naval ship battles, some kind of guild combat. Also changing how ilvl works in pvp.