World Of Warcraft players won't stay grounded in new expansion Legion. Designer Ion Hazzikostas says that players will be able to use their flying mounts while exploring the new zones.
During a live developer chat, Hazzikostas said that players can "eventually" earn the right to fly by earning a special achievement. The achievement will be introduced in Patch 7.0, the major update arriving before Legion's launch. While you probably won't be able to make any headway until the expansion goes live, at least you'll know what the requirements are so you can plan accordingly during your initial quests.
Flying mounts were introduced in first expansion pack Burning Crusade. In BC and later expansions, players could earn the right to fly by hitting the new level cap and then paying for a flight license.
Current expansion Warlords of Draenor broke with that tradition by not allowing flying mounts at all. Hazzikostas said in an interview they didn't allow flight because they felt it hurt outdoor exploration:
The world feels larger, feels more dangerous. There's more room for exploration, for secrets, for discovery and overall immersion in the world. At this point, we feel that outdoor gameplay in World of Warcraft is ultimately better without flying. We're not going to be reintroducing the ability to fly in Draenor, and that's kind of where we're at going forward.
These comments caused an uproar at the time among the player base. Players not only enjoyed the convenience of flying mounts but had also spent plenty of time and money to collect them.
The backlash led Blizzard to rethink their plans. Flying will soon be enable in Warlords of Draenor zones for players that earn a new Achievement. The Achievement requires players to do a lot of treasure-hunting and questing through Draenor. I'd imagine Legion's flight Achievement has similar conditions.
Hitting max level and running off to the flight trainer was a really gratifying moment in past expansion pack so. That said, there's always a plethora of reasons to be happy for hitting the level cap (new dungeons, new quests, etc.) I'm not opposed to pursuing an Achievement to get flight as long as it's not too much of a grind. It might take some time but at least I'll know the reward is worth it.
Legion will send players to the Broken Isles to stop a demonic invasion. The expansion will also introduce a new Demon Hunter class that can deal damage or tank enemies. Each character class can earn relics and access a special base of operations. The Honor system is being revamped with a new section of PvP abilities and bonuses. Everyone who buys the expansion will also get a free level 100 boost for one character.