Leveling characters post first level 60

Anybody have any idea how much, if it is, more efficient to pick Threads of Fate and level through world quests and instantly picking your covenant rather than follow the storyline again?

And if so, how much by?

The world quests give much less xp than the story quests. It’s only going to be faster if you’re a Healer or Tank and can spam dungeons (or can group with one).