http://www.pcgamer.com/wows-73-update-cuts-flying-mounts-to-encourage-exploration-says-game-director/

World of Warcraft: Legion's final major update, number 7.3, is now live having teased the battle for Argus at last week's Gamescom. While attending the conference in Cologne, I sat down with game director Ion Hazzikostas and asked why WoW's 7.2 update introduced flying mounts before the latest instalment dropped them.

"The bulk of the expansion [7.2] is set in the Broken Isles and we have this structure where players, once they've mastered that space [and] accomplished what there was to do, they could earn the right to fly—we're very happy with how that's worked out," Hazziokostas tells me. "Argus is a little bit different. I think it fits more of a mould of end-game zones that we've had going back to the Isle of Quel'Danas back in Burning Crusade when flying was first introduced—that in-game island, you couldn't fly there. Part of that thinking is creating a sense of danger and having players grapple with exploring the space from the ground, and Argus is a very dangerous world.