I misread your post and confused Kyrian with Nightfae, sorry. You're right, Nightfae is for Mages mostly the best Covenant (for Rogues in cases too, but that's about the Nightfae's "best" status overall).
- - - Updated - - -
On another note, Blizzard just completely destroyed any point Pelagos had to be taken, so many people have to reconsider which Covenant to take, as it won't be Kyrian anymore for most classes / specs.