What should be done is that you should remove all skill points from it (including the mastery bar, use GD Defiler) when 60.7 comes out. The name was changed in the backend for future compatibility with the expansion, so from the game’s perspective the old version is “gone” and there’s a totally “new” mastery that happens to be exactly the same.
Absurd energy costs have been reported. Interesting feedback on the exclusive auras, I thought the damage one was a pile of crap compared to the debuff one.