So, barely different than Warlords, since in WoD most players have already completed parts of the meta when it became available. The big difference is that there now is a carrot on a stick in form of achievement, and Blizzard shall give us a carrot whenever they damn please. Or not at all, I almost expect a "We think that no flying in Legion has really helped the overall feel of the game and we decide not to reintroduce it after all" post coming in the middle of the expansion.
If somebody tells you that he will do something for you "at a later date", you should be carefull believing him.