While many individuals claim that Holy Priests are stronger than Discipline in the current raid environment, priests must always decide for themselves what to play. However, with that being said, I find Holy to be strong and would like to see more constructed discussion/feedback with regard to HPriest healing on these forums. At the moment, it seems that no HPriest specific guide exists. With that in mind, I offer this as both a humble quick start guide to the HPriest new to raid healing in 5.0 and as a place for the community to begin profitable discussion. Please take my suggestions with a grain of salt as I am, unfortunately, not raiding Heroic content at the moment. With that admission having been made, I wish to be clear that this is a beginner's guide to HPriest and that individuals will need to make their own choices about what they feel comfortable with.
Section 1: Why HPriest?
While theorcrafting abounds, my answer would be that HPriests have strong direct healing, multiple tools through our Chakra to respond to different situations (keep in mind that aoe v. single target is not a helpful construction of Chakra. Rather, any HPriest in a raid setting should expect to do "mostly" multi target healing and should consider their Chakra as a tool kit to address the needs of a specific fight or even phase of a fight), and excellent cooldowns, specifically insta-cast cooldowns that help to keep us mobile and responsive in different situations vs. Discipline's much more "cast time based" style. Ultimately, you should consider the needs of your raid group and the specific fight, even respecing accordingly.
Section 2: Talents and Glyphs
Ultimately, you will need to respec and even reglyph for specific fights.
1st tier is your choice
2nd tier Angelic Feather gives multiple raid members a significant boost (or you one very long boost) to movement speed. Body and Soul should be avoided as Holy Priests should not, in general, cast PW:S (it does not benefit from haste, mastery, or crit; it is expensive; it does not heal for much).
3rd tier is very debatable. If you find yourself with significant down time, Solace does pull ahead of Mindbender for regen. Also, if you spam the spell "Heal" in your down time a great deal (as I do) FDCL can be very efficient. Personally, I prefer Mindbender as it provides a great deal of regen, a significant amount of damage, and is a one GCD "set it and forget it" spell. As long as you keep your Mindbender on CD (about 10-20 secs into a fight, usually), you will see good returns.
4th tier is up to you. I feel Angelic Bulwark, as it is a passive that provides the "healing" when you need it most, is the best choice. Desperate prayer, provided you have the presence of mind to use it, is great. However, it does cause you to hit one extra button at what is, mostly likely, a "desperate" time for healing. Your choice.
5th tier is a clear choice between Power Infusion and Divine Insight. Twist of Fate is excellent when it activates; however, if you are activating its effect enough times per fight to be useful, you are probably not keeping people healed as much as they need to be. Frankly, its only good when people mess up. the others are good all the time. As far as Power Infusion v. Divine Insight? I prefer Power Infusion. I, frankly, don't Prayer of Healing or Greater Heal all that often, maybe 4 times a minute total (they are more mana intensive and not as "smart" as many of our insta casts). However, Prayer of Mending is one of our best heals by far, and proccing an extra one that also does all of its healing instantly is excellent, especially as you will be getting the most procs during times of heavy aoe damage (epicenter, titan gas, etc) when you are spamming Prayer of Healing. This proc replaces one cast of Prayer of Healing for less mana and smarter healing. With that being said, Power Infusion, provided you time its cd to be up for all heavy damage phases, is even better as it no only allows for more of our strongest heals (Prayer of Healing, per cast, is very very strong) to be cast faster but also allows our go to spells (circle of healing, prayer of mending, Holy Words, and tier 6 talent) to be cheaper when we spam them. Power Infusion combined with Inner Will (for our insta cast spells) makes their impact on your mana pool very small. Your choice, but remember to USE Power Infusion if you take it. DO NOT SIT ON IT waiting for some imaginary time when you will need it.
6th Tier comes down to Halo v. Cascade. Divine Star isn't terrible but simply does not provide the benefits the others do. Halo is excellent for heavy burst damage WHEN YOU ARE AT RANGE from most of your group to be healed. This can happen a great deal more in 25 mans with their more substantial melee piles. For 10 mans, Cascade seems the clear choice as it will provide a strong (not as strong as 25 yard halo but equivalent or better to 0 yard halo) heal on a shorter cd for less man. Additionally, it is VERY important to note that, when in Serenity Chakra, Cascade will refresh your renews. One mana intensive but extremely strong form of aoe healing would be to go CW:Serenity, Inner Will, Renew 6/7 raid members, cast Cascade on the first raid member who was renewed (before the renew runs out). This will result in a massive amount of aoe healing over time that, if it does not clip into the cd on prayer of mending or does not cause you keep your circle of healing on cooldown more than a few seconds, will rock. In general, this is too mana intensive and does not provide a substantial enough bonus to justify switching out of CW:Sanctuary. Still, an important tool to keep in mind for predictable, high damage.
Glyphs are not as important as I would like. However, they can be useful. The first and most notable glyph is that of Lightspring. This glyph allows you the confidence that your lightwell will provide its healing regardless of your raider's willingness to click on it. As lightwell heals are very strong, very cheap (the casting cost of the well itself, especially when pre-cast, is very low), and come without you wasting your own gcds during periods of high damage, this glyph seems like a fine choice. HOWEVER, if your raiders are "smart," you may with to leave this unglyphed. With the glyph, your lightwell may use it's charges when your healers were in control of the situation, leaving your raid with an empty lightwell during periods of very high damage. A better but not always practically feasible choice would be to leave your lightwell unglyphed and to ask your raiders to click on it as a raid wall cooldown (treating it as another form of PW:Barrier from Disc or as a version of Tranq from druids). I prefer to glyph it. XD
For much the same reason as I glyph my lightwell to make it a lightspring, I also take glyph of Lightwell, to increase it's total charges. Typically, in progression content, you will have enough raiders, even in 10 mans, who periodically reach low health to drain the lightwell before 3 minutes pass. As such, this glyph notably increases the overall healing your lightwell does without increasing its cost.
Your third glyph is situational. If you are below the first important haste break point (which you should definitively be trying to reach) of 3039, you will use Glyph of Renew as it is strong in that situation. If you reach the second important haste break point (not as important as the first but very doable, especially if you favor a haste heavy healing style), you should also glyph renew as you will benefit both from additional ticks and stronger over all heals. If you are between these numbers, do not glyph renew as the loss of ticks does not justify the additional healing from each tick.
The other choice of obvious importance to holy is Glyph of Prayer of Mending, which increases the first heal by 60% but lowers total charges by 1. This is a very interesting glyph in that it fits different play styles and situations. If you find yourself doing a good bit of tank healing (more likely in 10 mans), this glyph is excellent as it allows you a strong, quick heal that also does some aoe healing over time. If you do not do much tank healing, you might prefer unglyphed as it will spread it's healing around more evenly.
All of these glyphs are up for personal choices and situational use. I, not being interested in the second haste breakpoint of 4721 due to my playstyle, will never take the glyph of Renew. I do, however, heal tanks a great deal so I take Prayer of Mending. A raid group with high awareness can skip on glyph of Lightspring.
Spirit, Spirit, Spirit. I cannot stress this enough. People talk about increasing "throughput" all the time. The only time that throughput is important is when people are dropping quickly (Arcane Velocity, Titan Gas, etc). While it's nice to have in those situations, adequate planning and cd management can, in my experience, always see you through. NOTHING, imo, beats being able to heal who you have to, when you have to, no questions asked. Honestly, most "throughput" (outside of heroic modes and maybe even then too) goes into overhealing as you have 1 or more other people frantically trying to top people off as well. In that regard, having spirit always means that you can do what is necessary, when it is necessary.
With that in mind, as a priest trying to gear, Spirit>/=Int>Haste(3039)>Mastery>Haste(4721>>Crit
The first haste point is very nice as it adds ticks to renew and HW:Sanctuary. The second is also nice as it gives ticks to lightwell, HW:Sanctuary, and allows us to glyph our renew. With that being said, I do not prefer haste past the first break point as I tend to rely on our insta-cast cds. With Inner Will up, they are cheaper, stronger, and can be cast while moving in comparison to Prayer of Healing (their main competitor). As these spells (Circle of Healing, Prayer of Mending, Cascade, and, unless you reach the next haste cap, Renew) do not benefit from haste at all (haste does not effect our mastery), I find mastery preferable. Obviously, mastery is only useful if people are not already topped off. Therefore, mastery benefits us most when we need it (high damage).
Spell Choice and Healing Style
Each healer must decide for themselves based on their gear, their raid comp, the fight, and their own play style "how to heal." The basic theory of healing, of course, is to keep people alive.
Let me say this again: "KEEP. PEOPLE. ALIVE."
This does not mean topping hps although that MIGHT help. This does not mean having max mana at the end of the fight because you are just that op. It most CERTAINLY does not mean that you should be competing with your fellow healers to see who is more op.
Rather, this means that you MUST coordinate with your fellow healers and your raiders to understand why people die. Sometimes, it is not your fault. If people stand in things, don't kill adds quickly, and ignore mechanics, they will all die. Period.
As a healer, you might, in those situations, spend more time "reminding" people to do their jobs and get out of the fire than actual healing. Sometimes...that is the highest "hps" you could do (preventing damage by increasing awareness).
Typically, healers do not oom unless their raiders are failing. If you or another healer is ooming with mostly if not full 463 gemmed/enchanted gear, you or those healers need to research their classes more.
I cannot help these other classes but I can help you!
The following is MY priority system that I use MOST of the time while raid healing. It is very mana efficient and relies heavily on knowing when and where damage will come from on the bosses, using the best heals at the best times. The reason it is so mana efficient is that I TRUST MY OTHER HEALERS! If all healers try to to do all the healing themselves, they will oom and over heal like crazy. Instead, each healer should trust their fellow healers. Remember, hot based classes like resto druids take time to fill those bars up. Don't panic if you don't see people jump to full immediately. They won't die! Instead, keep a calm mind and a clear vision on the next major source of damage that will be coming out. If you know when that will be, you can take your time to heal people back up efficiently without using much mana at all.
With that being said, here is my system.
Chakra sanctuary unless spike damage (Spirit Binder, some comps of Stone Guard) is high.
Inner Will unless using a casted spell, in which case I stance dance. If raid damage is very hard/very hard to heal, just go to Inner Fire for the duration. If boss has entered last burn phase and your mana is good, go to Inner Fire to increase throughput. DO NOT STANCE DANCE if someone is about to die (25% health). HEAL THEM!
Pre-cast Lightwell and refresh when it comes off of cooldown
Use Circle of Healing on cd if 4 or more people have taken at least 20% of their health in damage
Use Prayer of Mending if the tank's health drops below 80% or if a raider's health drops below 70% or if ticking raid damage has gone out (just eyeball it, no worries)
Use Cascade at the start of predictably high damage (Draw Flame, Total Annihilation) or when several people have taken 40% or more of their health as damage when you can't predict the next wave of damage (Stone Guard, Spirit Kings).
Stance dance and cast Prayer of Healing TWICE, once on each party of raiders, if significant raid damage has come out/is coming out (burn phase on Spirit Binder/Elegon [so much more so on Elegon...]). Remember to stance dance back to Inner Will unless your sure your mana is solid and major heals will be needed.
ONLY, I REPEAT, ONLY! cast Holy Word: Sanctuary if you are 1) 100% sure that 6 or more people will stand in it, 2) you are sure they will stand in it for the full duration, 3) you really need the extra healing, and 4) you are not in the middle of trying to heal people up in the first place.
HW:Sanc is a bit of a mini (very mini) raid wall. However, if people don't stand in it, if they move out of it, if even a bit of it is goes unused, you have wasted time and mana that could have been used on better, faster spells. It is VERY expensive, heals for VERY little (in the short term), and has a VERY small radius. I am not saying not to use it. Feng and Spirit Binder and Elegon and (maybe) ranged pile right before gas in Will are great opportunities. However, Stone Guard and Four Kings (almost) NEVER give you a chance to use it. Don't waste the mana.
Renew is a nice spell but not super efficient compared to Circle of Healing/Prayer of Mending. Use it sparingly on a tank (if they need it) or on a dps/healer who took some spike damage. Typically, I use it as filler when only one or two people have taken damage (and I don't want to waste an aoe cooldown) but I don't have the time (movement) to cast heal. I am not saying not to use it, just don't use it over stance dance cast heal if you can help it.
Save Divine Hymn for specific moments in the fight when healers will be chaining raid walls. Otherwise, use it when something bad happens (unmitigated overload on Stone Guard). DO call that you are using so that you don't have the stupidity of a tranq/hymn combo, overhealing the ass out of people for no good reason.
If you find yourself without a strong tank healer, you might use Greater Heal more than otherwise. I generally run with a pally or a shammy and mostly ignore the tanks aside from the occasional Renew and Prayer of Mending.
DO NOT use Flash Heal unless someone (usually a tank) has dropped below 30%. Otherwise a greater heal will do fine. Also, if you feel you might need to use Flash Heal, take a millisecond and check your own health. If you are 70% or lower, you should use Binding Heal. All in all, Binding Heal is similar to Flash Heal in power, casting time, and cost, while doing nearly twice the healing. It is much more efficient IF you need the healing.
If you do Flash or Binding heal, do not be in a rush to use your Serendipity proc. Instead, try to sit on it until you need a Prayer of Healing or, possible, a Greater Heal. Obviously, try not to waste it, but casting a spell (using mana) that your raid does not need just to take advantage of a passive proc ability is silly.
As far as mana cooldowns go. I would use Mindbender early and often but ONLY IF YOU CAN USE THE MANA. Generally, you will be able to use the mana.
I would try to save Hymn of Hope for specific moments in the fight. The later you use it the better as the more likely you and your fellow healers will need it and the more likely that you and your fellow healers will benefit. If you use it early, dps might actually be lower while healers will most certainly be lower at the end of the fight. Do try to predict when you will be able to use it. Obviously, allowing someone to die because you really wanted to channel a pretty spell is very stupid.
I cannot, I repeat, I cannot stress enough the importance of trusting your fellow healers, of healing efficiently, of knowing the fights so that you cast the right spell, at the right time, and don't waste your cds. There is nothing like the extreme satisfaction of pre-casting a Prayer of Healing into Cascade, into a Circle of Healing, into a Prayer of Mending and watching people's health bars barely even move during high, raidwide damage (obviously, this also requires your other healers to anticipate damage as well).
I also want to encourage communication. Your raid leader will have to decide how much chatter is allowable during raids. I am the raid leader for my group, and I encourage everyone to be as vocal as possible about what they are doing and what is happening. IT IS SO MUCH EASIER for healers to keep people alive if they communicate. Out of range of a tank on Stone Guard, call for help! Can't use your raid wall because of moving for fire? Tell people to eat cookies/someone else to use a cd. This applies to all your raiders. Tanks calling out taunts helps your healers anticipate damage, dps screaming for help killing adds keeps the raid alive. It's ALL ABOUT COMMUNICATION both before the raid, during the raid, and after the raid. Be aware, be smart, and help each other out!