The reality is Azeroth needs an extinction level event. I mean everything is literally laid to waste and must be rebuilt. There is your storyline.
The franchise and storyline has gone down a bloated, dysfunctional and disjointed path. It appears that its being cobbled together with aspects from Lord of the Rings, The Marvel Universe (Honorable mention to Thanos and Dr. Strange) and of course Hasbros Transformers. Yup now we have Machines running the planet. We now have Galakrond instead of Galvatron in wow lol. Might as well call it Cybertron with all the machines and factions involved with it lol. I can keep going on an on, but you get the point.
The point being this. WOW was fresh, original, expansive and wonderous. This is not meant to troll, but to put some creative perspective on a lot of this. I say this with peace and love.
There is no turning back now since the next 3 expansions are in the pipeline.
As for the next one…well time for an extinction level event. 
You all know I am right