The World of Warcraft team has some good news for Legion players who love to have as many alts as possible. While faction reputation will not become account-wide, a pair of very welcome changes will be heading into the game with the 7.1 update. Most notably, upon hitting 110, players will unlock world quests without the need to have attained 'friendly' status with each faction. This kicks in once a single character on an account has completed these objectives.
Reputation will not be made account-wide, no, but we will be easing a couple of linked features with 7.1.
First, Court of Stars and The Arcway will now unlock account-wide once each individual dungeon is completed once on an account.
Second, World Quests will no longer have the "friendly" reputation unlock requirement for secondary/alt characters. Once you hit 110 on an alt, you will immediately receive a quest to speak with Khadgar to receive your Flight Master's Whistle and unlock World Quests, as long as you've already unlocked World Quests on your main.
Hope this answers your concerns! :)
Check out the reaction to the big news on the World of Warcraft community forums.