A couple of developments in other games

[Alestorm]

I really do hope that Blizzard handles this Mentor-esque system better than SE does with FF XIV's.

The issues wont be likely be from Blizzards side, it'll likely go poorly because the community itself is so toxic. The fact they are "borrowing" ideas from this game and others says two things: 1. they're now realizing WoW is bleeding subs and need to try something to maybe slow it down and 2. plagiarism is now their way of coming up with new ideas. Especially since your relic weapon in Legion was basically an Anima weapon but more annoying to power up since NPCs did over half the work for you.