That's unfortunate. I'd much rather flying not exist at all so the game doesn't get ruined a few patches down the line for the sake of the 1% of the playerbase (look, I can pull numbers out my ass too!) who just want to fly and avoid conflict because they're bad or want to do world quests for that upgrade they desperately need to compete in LFR.
Also, yes, people did complain about flying prior to WoD. Maybe you just didn't play the game?
Though considering you won't preorder (you will, we know you will), that means it's more and more likely for them to not have flying in future expansions!
Now for the less sarcastic response: instead of complaining, push for the best of both worlds: DO NOT ALLOW FLYING IN WAR MODE. Simple fix, been saying it since Warmode was announced. Awesome, I know.
You want flying, I want to play the game and be able to WPvP properly; you won't be in Warmode, I will. Seriously just spam blizzard with no flying in Warmode and I won't give a shit if flying is implemented at the start of the expansion because it won't effect me.