*Skeptical* ME NO BELIEVE YOUso i've got a friend. He works in the game development industry. He recently got back on the horse for a new job after being cut from the zenimax online studios team in a design team purge. And though he hasn't worked with blizzard since 1993 when he was a qa tester on lost vikings, he still has friends. And some of those friends now talk to me.
Some of them at blizzard.
So this that i'm about to tell you is an honest to god leak, rather than speculation or guesswork on my part, but you're not going to be particularly surprised by it and i doubt many of you will care overly much... But here goes!
The world quest system is viewed by blizzard as a massive success and they intend to use it, extensively, in further expansions. You'll see less of the "standard" dailies with hubs like you did back in cata or pandaria, less progressive phasing like you did with the firelands questline, and more out and out world quest based area changes to fit the changing content.
It's not as salacious as "there's a new race!" or anything, but it's nice confirmation.