Boss specific recommendations and strategy:Raid Bosses
Tier 1 (15)
Schism is a strong talent that supplements the Discipline Priest toolkit very well. It is a hard hitting ability that also increases your damage done to the target for the next 9 seconds. Since Discipline Priest is built around its great ramps, you will want to play accordingly so that Schism is ready for when you are ready to burst with either Evangelism or Spirit Shell. Depending on the fight, you can choose to use it after consuming one or both of your Power Word: Radiance charges between the bigger ramps.
In raids, Twist of Fate is seldomly picked, and you need a high uptime when it matters (i.e. when you would’ve used Schism), but even that may not be enough. Schism is a 25% amp with a 150% SP hit, Twist of Fate offers no initial hit and only a 20% amplification, and as such has to offer you throughput outside of your Schism windows.
It is not recommended to play Twist of Fate if you pick Spirit Shell as your level 50 talent, as the talent itself should be played to prevent damage and Twist of Fate will rarely proc during your ramp.
Unlike Schism, Twist of Fate does buff your non-atonement healing, and as such with a Twist of Fate proc, your Shadowmends will offer very powerful spot healing. This makes Twist of Fate a good talent in M+.
Tier 2 (25)
Just like for raiding, Angelic Feather is the prefered option in M+ when in the need of a movement speed bonus. A downside to instead picking Body and Soul is that in moments where you need extra movement speed, there is a chance that you are afflicted by Weakened Soul from applying atonement on yourself, thus making it impossible for you to boost your movement speed.
Masochism deserves an honourable mention, it has seen a lot of play in high M+ to prevent one-shots and if you need the damage reduction to survive a mechanic to enable a strategy, giving up Angelic Feather can be worth it.
Tier 3 (30)
Since Spirit Shell now is on a 90s cooldown, the synergy between it and Mindbender is unfortunately not as good as it was before. The backside is that you would have to hold Mindbender 30s every time it comes off cooldown, which is a great loss of mana in comparison to playing Power Word: Solace instead.
Just like with Spirit Shell, Power Word: Solace is the better option if you are playing Evangelism since you would also have to hold Mindbender to sync it with its cooldown. In addition to that Shadowfiend (which Mindbender replaces) is appropriately enough on a 3 minute cooldown, which means you can use it every second Evangelism or Spirit Shell.
But, if you’re playing with double legendaries as a Kyrian or with Sphere’s Harmony, you’ll be able to have a big ramp every ~2mins, thus making Mindbender a viable option once again in that specific scenario.
In M+, Mindbender is a solid pick if you can use it on CD and get good value out of it. If you don’t get the full value, such as keeping it on cooldown for too long, Power Word: Solace is a perfect contender. Keep in mind that Mindbender replaces the 3-minute cooldown Shadowfiend. Shadowfiend hits harder and can be a good cooldown when there is heavier damage.
In M+, Power Word: Solace is also a good option. It gives you an instant button to press when you need to dodge annoying mechanics and still heal at the same time! Mindbender is an alternative to Power Word: Solace if there is a lot of running and downtime in the dungeon.
Tier 4 (35)
Shining Force in the level 35 utility row can have some niche use. From experience over the past two expansions, Shining Force has seen some use in raids, such as knocking adds back on Aggramar, forcing those irritating Psychophages on N’zoth away from you or even as a reverse death grip if your raid leader has to be creative due to setup limitations.
In M+ Shining Force can be used to knock mobs out of sanguine or used on the tank to help create a distance when needing to kite. Just be careful not to push the mobs into another pack as the knock itself is very powerful.
Tier 5 (40)
Sins of the Many is the default pick. It is a flat gain with no downside, unlike Shadow Covenant which can do decent healing, but the tradeoff being the high mana cost and locking you out of, in particular, dispel, feather, Desperate Prayer and Pain Suppression.
Sins of the many is the default pick. It is a flat gain with no downside. In M+ there will be downtime where you don’t have to heal anything but the tank with atonement and then you can get juicy value out of the full 12% damage buff!
Tier 6 (45)
Purge the Wicked is the default pick for this row in both raids and M+. Whenever you add a second target to any encounter, Purge the Wicked pulls ahead of the alternatives, and the better you are at not having to spend mana on refreshing Purge the Wicked by using Penance to spread the same Purge the Wicked debuff back and forth, the better it becomes.
Divine Star is quite good if you need regular aoe healing, if people are on top of each other regularly, or for some additional aoe DPS.
Purge the Wicked is the default pick for this row in both raids and M+. Whenever you add a second target to any encounter it pulls ahead in numbers in comparison to the other two alternatives.
It is also very difficult to pull off Halo in a dungeon without accidentally ninja pulling half the instance. It is also hard to make good value out of Divine Star, since people are not always stacked up. This leaves Purge the Wicked, which is a solid option. The dot spread mechanic through penancing a dotted target saves global cooldowns and mana when playing.
Tier 7 (50)
Evangelism is the tried, true, and tested talent that discipline mains from Legion and Battle for Azeroth will be very familiar with. It’s a flat 6-second bonus duration to all active atonements. This talent is great for encounters with an extended period of heavy damage where you will not overheal, and Spirit Shell doesn’t cover it.
Lenience is the default pick for mythic+. It gives you a slight damage reduction for your tank and overall the alternatives are not very impressive for Mythic+ since it is 5 man content and they both synergize better with bigger groups.