Originally Posted by
Yarathir
I don't know. I considered WoD a filler expansion because it really didn't give us anything noteworthy that we couldn't have gotten without it.
Yes, it gave us a new Gul'dan that could bring in the Burning Legion, but otherwise, what did it really give us? The story of Draenor barely really affected us, it was like a self-contained timecapsule. All we did was lose our main universe Maraad. There was nothing else of consequence.
Yrel, Grommash and the rest were never seen again as Blizzard wanted to close the book on WoD altogether, so we gained nothing, and we lost something.
That's why WoD was a filler expansion: without it, we wouldn't have lost much.
At first glance, BfA might be a filler HvA expansion, but they've already made it clear that that story is interwoven in the Azshara and N'Zoth story people have wanted, and those are far from "filler".