Nice concept, but is really needed? If you want help level fast your friends the place are duties, and there is already the sync.

And quests around aren't so difficult, you can done them all solo. If happens something difficult, if you really are a friend to them, you let them overcome solo that difficulty, to let them learn their class. Or else we end up with more tanks that doesn't know what aggro is, or healers that doesn't heal, or dps that does not know what a rotation is. There already are enough of them