I recently rekindled my interest in my healer, including both raid and PvP environment. Concerning raids, it is really not a big problem. Specs and tactics are well laid out over the internet and never found it difficult to do the research it needed. In most cases, I am easily out healing most other healers with lesser gear. However, when it comes to PvP things get a lot more difficult; specs are highly adapted to play styles and even spell selections and priorities seem to shift greatly between players. Navigating this maze can be a bit daunting sometimes, so figured I’d upload some of the things that I’ve personally found.
There are really two ways to play a discipline priest on the arena, and PvP in general, and that’s defensively and offensively. If you only stick to battlegrounds, you might want to go defensive because you can count on your group doing the necessary damage but on arenas, at least when approaching the higher ratings, you need to shift more and more to the offensive and the common tactic is to hit the opposing team hard in the very beginning of the fight.
The way that discipline priests deal damage is essentially two folded; either via shadow spells, such as dots and Mind Blast, or through holy spells, such as Holy Fire and Smite. The camp is divided between these two schools and both have strong arguments towards them, so lets go through them.
Firstly, dealing damage through shadow spells means your primary burst spell is Mind Blast which is accompanied by Devouring Plague and Shadow Word: Pain. It is a good combination but I find it inefficient due to how slow it is. Mind Blast has an 8 second CD and the DoTs tick really slow. But then again, it has the benefit of not requiring a lot of work on your part. You can just drop out of LoS, hit the target with DoTs and a quick blast, before disappearing again, and after that you can completely focus on healing again.
If you forego this method, you can try doing holy damage, but this specifically requires that you spec for it, while you can still use shadow spells with a defensive spec. Then again, there is no resistance against holy damage and the combination of HF + Smite + Smite does a lot of damage, very quickly. The only weakness it has is the fact that if you get counterspelled while casting, it will effectively lockout your holy spells, including all your heals for 8 seconds. Needless to say that can be very dangerous.
For a spec, I suggest you take a look at the one below. It often tends to draw a lot of negative feedback from disbelieving priests who do not understand its potential, but I have seen quite a few priests swear by it and do very well. Again, it also comes down to your personal flavor.
The most important talents for this spec are Divine Fury and Searing Light, and do not forget the Glyph of Smite. They all add to the damage of your smite attack, which can be 6-7k on a successful crit, depending on your gear. An argument could be made that speccing so high on damage takes attention away from defensive abilities and indeed, they are valid. Tbh, I cannot see the whole spec working unless you are sitting on some pretty good gear, which makes it possible to rely on it to supply the necessary protection.
You could make a case for taking the three talent points from Rapture and putting them elsewhere, like Grace, Improved Renew, or Spell Warding. However, having Rapture doesn’t just increase your own mana efficiency, but helps your partner pump out more damage. If you insist on letting it go, I would recommend either of the two last choices. There seems to be too much target switching to effectively use Grace. Improved Renew helps both you and your partner, and again, if your gear allows it, it might be better to forego the extra mitigation from Spell Warding.
No matter which route you take, remember that, as a healer your damage will never be awesome. It is simply a little bit of extra to help your partner out. Also, the specifics of your spec, like whether or not use Rapture, etc. largely depends on your team mate(s) and your personal play style. Find what works best for you and go with it. Be open to suggestions, but let no one tell you what to do, because at the end of the day, discipline is a highly versatile class.