It's pretty obvious after seeing the movie that Warlords of Draenor was in fact made just to coincide with the movie. I would even go as far to say that Legion was planned after MoP (all the lore signs are there) and when the deal to make Warcraft the movie was made, they decided to slip in WoD in between MoP and the original next expansion: Legion.
I think it was pretty obvious to the playerbase it was a rushed expansion, and as someone who has played Legion beta, why that expansion seems incredibly fleshed out. They probably got to iterate on so many new ideas with Legion because it was planned so far in advance, while WoD was just a quicky.
On one hand, I don't think I'll ever really forgive the crappiness that was WoD, but on the other, as strictly a Warcraft gamer (not huge on the books), I'm not sure I would've had the familiarity with the old Warcraft orcs I did for the movie if we DIDN'T get WoD.
Blizzard probably knew that WoD might be bad for "World of Warcraft" but would help with the "Warcraft" IP to make their playerbase make connections between the game and the movie and maybe be excited to see particular lore heroes they just recently interacted with in the game.
So for many of us who were scratching our head at the whole WoD expansion, after you see the movie, you'll see why it was made.