Is Harsh Discipline an absolute must? It is powerful, efficient, allows you to do what you want as a disc priest (store up burst dmg to maximize atonement value), and it’s fun! A quick search for recommended builds and I see they all include Harsh Discipline too.
But if you’re 100% taking Harsh Discipline, then of course you’re also going to toss 1 more point into Twilight Equilibrium below and Lenience/Evangelism above. That’s 4 of the 10 point’s we have available in the bottom part of the tree :\ I feel like finishing out builds is incredibly inflexible due to this.