Warlocks being over powered in one form or another has been a consistent theme throughout WoW's life. Blizzard should of removed them long ago, then, seeing as in comparison flying only just became a problem 6 months ago.
And when did Blizz ever try to balance flying if they thought it was OP? How is removing it from max level better than tweaking the elements of it the dev's consider OP? Especially when I have paid them a premium, an additional cash payment on top of my sub to obtain and use the shiniest of flying mounts.
And ALL of the mounts they sell are flying mounts. 100% of them. THEY KNOW THE VALUE OF FLYING MOUNTS. Ignoring everything else, why would they severe this revenue stream, when they have worked so hard to foster and cater to it? It makes no sense to remove it.