21/40/0 trades the two points in Imp. DS to fill out Emp. Healing. The math on this is long and hard, but as I understand it, the upshot is that Emp. Healing will do more for your own healing, but Imp. DS will do more for the group, assuming it includes at least three casters (counting yourself). Therefore, if another priest in your usual raiding group has IDS, you should take EH instead.
But if you're skipping IDS because another priest will be buffing DS, why even take the DS talent? That leads to the 20/41/0 build. Unfortunately, in my opinion, Circle of Healing is still a terrible 41-point talent, especially for PvE. As I stated in my priest column on heals, I haven't actually ever had Lightwell or CoH, so I can't say for sure, but from the numbers I've seen, as well as opinions from other priests who have had it, it's just not worth it. On the other hand, a few people over at the aforementioned Know Your Heals article liked it, so your mileage may vary. It's much more helpful, in my opinion, to have DS available in case you might need it in a 5-man or a raid that happens not to have another priest.
But let's say, as in my case, there isn't another priest that regularly raids with you that has IDS. Then it's pretty worthwhile to take it, since you're boosting the output (and spirit) of every caster in the raid, including of course yourself. But where to allocate the particular points?
Discipline is the most straightforward; let's start there. Although it is a mess of a tree without any real focus, we know what we're going for here, which is DS/IDS. On the way is one more absolute must-have talent for any raiding priest: Meditation. Letting some of your Spirit ignore the five-second rule (5SR) is indispensable; fights like Curator would be practically impossible without that degree of mana regeneration, I think.
At the top we start with a choice between Unbreakable Will and Wand Specialization. I've discussed this issue before; I choose Wand Spec outside of PvP. In group PvE, if a mob AoE fears, you want to get hit by it. Why? After the fear hits, the mob will go for the highest person on its aggro list that isn't feared. Typically, the healer is the second-highest, after the tank; therefore, if you have a high resistance to fear, it's going to happen reasonably often that the tank will get feared, you'll resist, and the mob will stomp you. No good. Besides, Wand Spec helps a bit when soloing -- and believe me, you'll need all the help you can get there.
Improved Power Word: Fortitude is of fairly marginal benefit; it adds 237 health to your top-rank Fortitude, less than one hit in almost all cases, and less than half of what my Renew ticks for. However, it's still worth taking to lessen arguments about who's going to be doing what buffs, and there's not a whole lot of competition for those talent points. Moving on, we put the full five points in Silent Resolve, because less threat is always a good thing. Even with that I still sometimes pull aggro in places like heroic Underbog, where I have to just spam top-rank heals on the Bog Lords simply to keep the tank alive.
Now we hit my favorite talents in the tree so far, Inner Focus and Meditation. Both of them are efficiency talents, and if you haven't figured it out by now, efficiency is the name of the healing game as far as I'm concerned. Like I said earlier, Meditation is super for those long fights; for me, it's the equivalent of about 45 mana per 5 all the time, on top of the out-of-5SR regen and spellpower boost I already get from spirit (via Imp. DS as well as Spiritual Guidance).
Inner Focus is somewhat harder to quantify. (It gives you a free spell with a 25% higher chance to crit, on a three minute cooldown.) If you just discount the cost of an expensive heal (usually Prayer of Healing) every three minutes, it comes out to a savings of 35 mp5, but it also helps you out in regen -- if you've been out of the 5SR for 10 seconds and you cast a spell, usually that kicks you right back in and you don't regen properly for another five seconds. However, if you Inner Focus that spell, it doesn't trip the 5SR (because it doesn't cost any mana), and your regen continues.
That gets us to Mental Agility, which gets 4/5; although we do cast a fair amount of instant spells (Renew, Shield, Prayer of Mending, buffs), one point there is less valuable than one point up above in Mental Agility or Imp. PW:F. And finally Divine Spirit and its Improvement, which I've discussed above. Spirit is already important for this build; a buff that gives you more of it is great, and making that spirit have extra effect not only for you but also for anyone you cast the buff on is quite nice.
Now Holy. Holy has always (as far as I know) been a troubled tree. It seems to be meant to be the PvE healing tree, but it's been crippled by unusually weak 11/21/31/41-point talents. At the moment, out of those four -- Holy Nova, Spirit of Redemption, Lightwell, and Circle of Healing -- only one, SoR, is considered a must-have talent by the majority of healing priests (I believe), and that mostly because of its passive benefit, +5% spirit. The situation was certainly no better when Holy Nova was the top-rank talent and SoR was usually referred to as "Improved Death," lacking the spirit boost.
However, Holy's not all bad. It's just that other trees have superstar talents in those key positions, and Holy prefers to keep its real goodies elsewhere. For instance, look at the top tier: if I could, I'd max out all three of those talents. Healing Focus is a must-have, because when you're getting hit is the last time you can afford to be losing cast time. Imp Renew takes one of our core heals and strengthens it considerably. Holy Specialization is a great dual-purpose talent, healing and offense. At first it may not seem that strong for healing, because a crit heal is more often than not an overheal, but Inspiration should also be taken into account. (Side note: I also wish the item designers would take Inspiration into account, as in my set of priest-oriented gear I have zero spell crit rating from items.)
As it is, I find a need later to remove a few points from talents I would prefer to max out, so I only have 4/5 Holy Spec in my build, though it was a tough choice where exactly to take points from.
The next tier is a stroke of genius from the talent designers, in my opinion. One talent strongly motivates early investment in the Holy tree, improves both healing and offensive capabilities, and motivates the switch from Flash Heal as staple heal to Greater Heal as staple heal which the devs clearly wanted to take place in patch 1.10. That talent is of course Divine Fury. I've heard it called the only talent in Holy a priest really needs to heal well, and there's some truth to that; a 2.5s GH seems virtually -- if not actually -- required in most endgame encounters. 5/5 here is a must.
Inspiration gets full points, despite the fact that I have a low crit rate and try not to spam heals. I believe it's still fully worthwhile, since mitigation figures get really big whenever it hits on a well-geared tank. There's nothing like healing damage and at the same time preventing more incoming damage; Prayer of Mending and the 4-piece bonus on Avatar Raiment (T5) have similar effects. However, it's been a while since I've seen any math run on this talent; anyone know the numbers?
Improved Healing is another no-brainer for an efficiency nut like me. 15% off my most commonly used spells? Yes please thank you. Spirit of Redemption, as discussed above, is here more for +5% spirit than for being able to heal a bit after I die; I've seen a few encounters saved by me in spirit form, but not many.
Whether Healing Prayers is worthwhile depends, in my opinion, on whether you do more 5-mans or more raids. If you do 5-mans, take it, if not, not. I simply find myself using Prayer of Healing all over the place in heroics and even regular group instances, but hardly at all in raids. Raids are more likely to spread people out, and of course there are other groups besides your own -- and most of the time, the other groups will be taking the majority of the damage. It also discounts Prayer of Mending, which I use all the freaking time, but the spell is already so cheap it doesn't make a huge difference. I have it in my build because I do a fair amount of heroics. This, by the way, is the aforementioned reason I had to take points from talents I wanted to max out. If I was going for pure raid healing, I'd drop Healing Prayers and restore a point each in Holy Spec and Spiritual Guidance.
Speaking of Spiritual Guidance: this is a somewhat controversial talent, but we're seeing more and more spirit on Priestly items, and the talent gets accordingly more and more powerful. For me, I get +22 damage and healing per talent point, and as I get better gear, the talent gets stronger. When this talent was released, back in 1.10, I literally grinned for hours at hour clever it was; Spirit was always meant to be the core Priest stat, like Intellect to a mage, but it took until SG gave spirit a peripheral benefit to really make the stat shine.
Spiritual Healing is another dynamite talent; you simply can't beat 2% more throughput per talent point, especially now that it applies after +healing from gear. 5/5 no question. Holy Concentration? Again a bit controversial, and again something that would be more useful if the Priest healing style was as spammy as the Paladin style (no offense, Pallies, I'm still jealous of your efficiency). However, it does seem to come pretty often when I need it, and like Inner Focus it can help you spend more time out of the 5SR. I would like if it worked on offensive spells as well, or if it had a higher proc rate, but I'm reasonably satisfied with it as is.
Now we come to a talent that perplexed the bejeezus out of me until I realized that +1000 healing is in fact a reasonable baseline number in BC. Empowered Healing just looked silly in patch 2.0.1, when a priest in MC epics was hovering around maybe +300. But now it does pretty well, and does better the better your gear is. It adds 65 per talent point to my Greater Heal, and half that to my Flash Heal, which is not too shabby at all. If I was going for 21/40/0 this is where I'd put my extra two points, probably. But I don't have that kind of room in the build now, and so it takes my last three points for 3/5.
Well, that may have been my longest Build Shop ever. Thank you for persevering, true believers. As you may have noticed, I've spent a lot of time thinking about Priest talents. And although this may be something of a cookie-cutter build, I feel it's pretty well reasoned out; what do you guys think? And keep sending in those submissions! See you next week.