Originally Posted by
Yunzi
It sucks? Really? So when the group is high health (pre-pull, early-pull, "downtime") you have two options - DPS and Clarity of Will. If your group is pushing the content it's a bad idea to try to squeeze in Disc's minor DPS - instead just Clarity of Will, preparing the group very well when the damage starts rolling in.
Even in difficult content there are lulls in every pull - points where you've caught up and there's nothing to heal. That's a great moment for Clarity of Will. Then when the lull ends the group will be in much better shape than if you spent those GCDs doing minor damage.
I second the mention of getting rid of Mastery - it's a really bad stat for every content in the game besides raids. Have a separate gear set for M+.