You could argue for Replenishment being less than what I've listed, which is "always below 100% mana". Most fights where I'm holy, I run between 80 and 85% of theoretical max return on Replenishment, so drop that number by as much as 3.4k.

For example:
XT (6:16 fight), 17.1k mana from replenishment, mana pool of 22,000. Max is 20.7k; 83%.
Kolo (3:59 fight) 11k from replenishment, mana pool of 22,800. Max is 13.7k; 80%.
Hodir (4:18 fight) 13.5k from replenishment, mana pool of 22,800. Max is 14.7k; 92%.

We tend to run 3 replenishment sources in a raid, so the buff *very* rarely falls off. Ticks might be lost due to being at full mana, or weird refresh bugs, but it's valid (at least for Fusion) to say 85% return on theoretical max for Replenishment.

I'm not running low on mana due to lack of having Test of Faith. It's not a matter of having to cast one more heal to top someone up the final 10%. It's more proactive healing; if everyone is topped up, queue up a heal on a tank, or toss off a PW:S. Refresh a Renew on a tank. Put PoM back up.

It's not that I'm starved for mana, and desperately need regen. It's that I find the ability to be proactive far more useful in a raid setting than a little more throughput. I agree that Test of Faith is a great talent, and I may eventually pick it up. For now, being able to watch the raid and haste people out of <ground effect #1516> is more useful.

I have not seen much of Ulduar so I cannot tell wether I will go oom much or seldom. But my Mana got to neer 0 more than once. We were there with 5-7 Healers. And I went low in Mana with 5 Healers and with 7 Healers. Maybe that should not be the case if our server would be more stabel (we have lags of about 2s all the time).

Anyway even if I would not have such problemsm your argument that many holy priests end up with some mana is not valid. Ulduar is about burst-dmg followed by low dmg. So the best thing a healer can do is burst heal followed by less heal. Priests, especialy holy priests, can burst huge chunks of heals for a high mana cost. So they can go low in such a burst phase, even if they will end the fight with much more mana because they could regen afterwards.

In BC you could use SP as a form of Regen-Stat since you had a big arsenal of different sizes of the same heal. Now it is much more binary. So you either have the mana for the biggest one or you dont. If you dont have the mana (or cannot sustain the mana for that heal over the whole encounter) you have to switch to something else. The difference between 2 spells is much higher in throughput than some more or less SP.

As for your argument that if someone heals for 300 (or something) more the char healed will live longer (what you wrote to counter the haste-argument): There are two szenarios that could end in a better survivability: less heals to top him up or more hits until the char dies.

300 (or whatever) Life will seldom make the difference in heals you need to top one up. And if it would make a difference you simply would not use another heal for it while raid-healing (maybe a chainheal or a PoM would jump there but If the char would have been at full life the jump would not have done much more, since it jumps to the char with lowest health in range).

So it has to be the other way round. Does 300 (or whatever) more life help to survive more hits? At the moment I cannot think about anything ticking for less than 2k so while there will be the possibility that 300 life may be all you need to survive another hit the chances are very low. Your heals have to make much more of a difference in size to enable the char to survive another hit.

Here's the key phrase from the post, emphasis mine:

Regarding talents, I strongly disagree that you can pick of "any of the talents you want". Just like all other classes, we have talents that are good for raiding and talents that are bad. Just like you wouldn't expect a rogue to pick up "whatever" and deal the same raid damage, a holy priest cannot just take "whatever" and be similarly effective. Yes, there is some room for tailoring talents around particular play styles, and each of those play styles can be optimal for a certain fight. But the number of flexible talent points we have is not that great. It's roughly 10, and there aren't many options to choose from.

Well I'm not suggesting you cut Body and Soul for it. Rather, I think you should cut 3 points in Empowered Healing.

And if proactive healing is the only reason you are running so low on mana that you're taking 65 intellect over 125 spell power, wouldn't it be better to let other classes do that proactive healing? Proactive healing only matters when the whole raid is at full health, so surely the other healers can give you a spirit regen break.

Think of a gem slot, now think of pure stats, 19 SP = 16 Intellect, so naturally on that base 125 SP is better on stats alone.

How can you suggest more SP ALWAYS leads to more OH? Consider Ignis where most of your POHs/CoHs are hitting and doing their job, how is +100 (says 80% coefficient) going to waste? In fact, you are actually saving yourself and other healers a cast or 2 in the long run (definately arguable since sunwell anyway when mana limitations basically got removed).

I agree, my toon is current in all haste gems as i try to find a limit between oom and best hps (550 haste rating as of last night). Personally, I get an innervate every fight so i can afford such a luxery. With so much haste now, SP becomes even more valuable as i'm pushing more out. Until I literally run 100% oom haste/SP consumables are better than Int/regen based. No point in having 30% mana when as boss dies.

EDIT: Spelling.

Sure, but there certainly is a point to still being on 75% mana when the boss is at 10%.

The length of fights and the healing required cannot be predicted with a high degree of certainty. If a couple of DPS die early, or a healer disconnects, or if you're 5% short of killing Kologarn's arm before another grip, the amount of healing you need to pump out during the course of the fight can change significantly.

In other words, better safe than sorry.

Note: I'm not arguing you should gear and buff exclusively for regen (I certainly don't).

It seems like serendipity has been fixed so that it can only be used on a single cast now. You may want to adjust the rotation in the opening post. I think it would now depend on the situation whether or not you cast that second PoH straight after the CoH, or cast 2 flash heals to gain a serendipity boost.

Confirmed in a blue post

Source

No, no, no -- all experts agree that the real problem is that all the other experts are wrong.

I'm definitely in the "regen is king and throughput is of secondary importance" camp. Even when not doing progression content, I only grudgingly accept that it may be ok to add mostly throughput stats.

I find the discussion here interesting, but I think much of it misses a very fundamental situation with healing that makes it very different from DPS: You always have more HPS than you need. You have to. If you don't have more HPS than you have damage coming in, the fight is over -- and over right away. Think of it like an evolutionary biologist: raids without excess HPS don't exist because they immediately go extinct.

That really changes everything, and any model which assumes increasing output generally increases healing "effectiveness" is fundamentally flawed. That's a good model for DPS, but it is inappropriate for healing. Adding throughput buys you a little insurance against rare, unlucky spikes in damage, so it isn't worthless. However, the diminishing returns on increases in throughput are rather harsh. That extra throughput only rarely ends up preventing deaths.

Some may argue that if you have superfluous HPS, that you should simply replace healers with DPS until you do not. That makes perfect sense.... except then you tend to run into mana problems before you run short on HPS. Don't believe me? Try it. (In fact, you will probably run into range and line of sight coverage issues before you run short on HPS).

There are very good mathematical reasons for this. If you look at your raid aggregate HPS as you increase the number of healers in raid, you will see something very much like a Michaelis–Menten plot seen in enzyme kinetics: it goes up linearly at first and then flattens out. Take a look here for reference. It is a hyperbolic curve that flattens as the effective HPS from the raid matches the incoming DTPS -- a flattening which definitely will happen by the nature of the situation: you can't heal more damage than you take. Importantly, you HAVE to be on that flat part of the curve where adding more throughput yields a terrible return, because if you're not, the raid dies right away. Put another way: more healers mostly means more healer competition to heal incoming damage and ultimately means each healer's effective HPS gets farther and farther from their maximum possible HPS potential.

In contrast, your raid healer longevity gets returns which are generally better than linear as you change the number of healers. Double the number of healers, and you roughly double the aggregate mp5 (and starting mana pool) between them, but you also decrease the rate at which each healer is casting, which decreases the rate at which each healer burns their mana and increases each healer's oofsr time. Consequently, scaling of healer longevity is significantly better than linear as you change the number of healers.

So what generally happens when you decrease the number of healers in raid? Your raid aggregate HPS decreases slightly, but your raid aggregate mp5 takes a more-than-linear hit the whole way. It is completely unshocking to see mana problems before HPS problems as you decrease the number of healers you have in raid.

Granted, I'm leaving out many details (in the interest of time), but those are the big dynamics. It is certainly possible to have so much excess mana and mp5 that the minimum number of healers you can have is then limited by their maximum HPS. In very short fights, that will happen. For long fights, increasing your maximum HPS may be nearly pointless because you are limited by mana before HPS becomes a limiting factor. To me that's where the dogma that "mana is king on progression content" comes from. Those fights are long.

Still, the most important and invariably true point is that healer throughput must already be present in excess in raids, so adding more gets you relatively little return. Discussion about how adding more spell power can increase your maximum HPS by X leaves me with an overwhelming sense of "so what?" You need to make the case that increasing your maximum HPS actually saves lives, which is far from obvious. Increasing your own effective HPS doesn't show that. Usually, all you are really doing is sniping potential HPS from some other healer and not saving anyone who would not have been saved anyway.

In addition, decreasing the number of healers is an unlikely benefit of increasing throughput. If that is your goal, you are better off adding regen stats since longevity is more sensitive to changes in the number of healers than throughput.

Yes, I agree, and what I like is that you're pointing out that the probability of a target living is the relevant metric to optimize, not the amount of damage healed. Damage healed is what statisticians call a surrogate marker, since it doesn't directly measure what you're interested in. It is not even a very good one, IMO, but we're probably stuck with it. The distinction is important because it is easy to mistake such metrics for real ends in themselves.

I will offer another take on this by looking at 10 man Ulduar.

Running 10 mans with 10 man equipment only is really a bit different. This could already be witnessed in Naxxramas when running with early equipment (remember 2-healing Sapph w/o fr in blues?) and some crafter stuff and now of course in Ulduar.

- There is a lot less heal sniping than in 25 man and also a lot less redundancy.
- Mana regeneration is very important when running with 2 healers and much less when running with 3.
- There are no muddled waters: when you make a mistake - sometimes a small mistake - characters die. End of story.

So how does this apply to the mana reg/throughput discussion?

Well, perhaps the difference is seen clearer. We cannot change the number of healers by 20% or so. We choose between 2 and 3.

In Ulduar 10 man so far, 2-healing is pretty difficult, 3-healing is fairly easy. 2-healing cannot safely be done with pure throughput equipment (at the very least not with entry level (aka Naxx 10) gear) - mana regeneration equipment is necessary.

Why doesnt' spellpower help?

Spellpower is only an efficiency stat, if it leads to casting less.

10-man:
Without healing sniping, spellpower only conserves mana if the additional spellpower enables us to cast less. So far, I haven't seen this to be the case. The very big mana burners are PoH, some CoH and in some cases GH. None of these is cast less with more spellpower in 10-man. There's not even the old serendipity where overhealing on FH/GH more frequently conserved some mana.

25 man:
It can - perhaps - be argued that statistically, with more spellpower, less casts are required.

To prove that spellpower really can be an efficiency stat, we would need to show that we can cast less by stacking spellpower as far as possible as compared to a more manareg oriented setup. Can we do that? I don't think so.

And for the real science part, I'd like to remind that our main goal is not to have maximum hps, but to keep everyone alive. It seems something obvious, but we really ought to remember it.

Maximizing hps (even effective) doesn't mean minimizing death probability. It really depends on the incoming damage pattern. Think of the frost bubble chains on Kel'Thusad : to minimize death probability, you want to heal every one just a little, not one personn with a very strong heal...
Another point would be to consider the hypothetical case of a long cast time high hps spell. It might be your highest hps spell, but you may won't use it often, because it won't fit the damage pattern.

I'm still seeming obvious, but that's the whole conclusion. Real sciences in healing requires a damage pattern, because that's all about timing the right heal just at the right time (after the damage). Unfortunately, we are not able to have good damage pattern for each fight. Therefore, I really don't like the theory "Maximizing hps requires you to stack haste / spellpower / Crit (put your prefered stat here)". There is really an "art" part, which is what spells we use at what time for what damage : that is this art we learn during the first tries on each boss, and it is really more important than transforming crit in spellpower in haste in spirit. More importantly, depending on our heal selection art, the science will change its answer ;-)

PS : I'm not saying that theorycraft is useless. I'm myself a theorycrafter, and I love it. I just say that we need to understand the limits of theorycraft. And they come early.

I like the angle that you're approaching this from, but I think some of your examples actually argue the opposite of what you intend because the line that I've quoted seems flawed. You're arguing that because healers will have to cast more they will see a non-linear decrease in Mp5 thus regen is more important. This seems to miss the fundamental point of dropping healers for DPS: the fight should take significantly less time with more DPS which is why Mp5 becomes less important. Take Hodir for example. Our first live kill we brought 6 healers and the fight took 5m27s. When testing out hard modes we've made attempts with 3 healers and the fight is closer to 2m30s (and to meet the timer would obviously need to be less than 2m). Clearly the encounter mechanics give a much bigger decrease in time with just a few more DPS, but the point stands that you can't argue that fewer healers is a net decrease in Mp5 without also accounting for how much shorter the encounter would be. The Mp5 from starting mana pool, shadow fiend and innervate, for example, sky rockets when you look at a 2m fight compared to a 5m fight.

Once you realize that this part of the argument is flawed, I feel the rest of your argument actually runs counter to the point you were trying to reach. We both agree that there is a maximum RHPS necessary, but since you've already dismissed "bring more DPS" as a bad strategy you use your max RHPS theory to prove that extra throughput is bad. I contend that "bring more DPS" is still a sound theory and in that context max RHPS is exactly why I gear for throughput. I think a lot of people run with too many healers; this thread is littered with comments of "why gem for bigger heals when someone else is just going to come through and heal that up". When I'm assigned to heal a group (or two or three) or an area, I'm the *only* person healing that group. With the prevalence of burst or RSTS effects, I need people to be at full in the fewest number of GCDs possible. Haste, crit and SP help me with this; regen does not.

Is my healing strategy "right"? Well, it works for my guild, but I would never imply someone else should do it that way. My only point in posting here was to demonstrate that people who say "regen is the only thing you should worry about in progression" are operating within a specific framework of raid healing philosophy that isn't necessarily accurate for all guilds.

I certainly prefer throughput myself and blasting through a boss with more dps than normal is extremely fun. There still however seems to be an underlying balance of regen which I can never really find a happy median for. For example you use the magestic dragon figurine which is a regen trinket over other throughput trinkets that are reasonable easy to obtain. You could also move points to Blessed resilience which would provide more throughput. I swap out my trinkets quite a bit but still haven't found a good medium. I used the spark of life(haste trinket) on kologran last night and ended the fight very close to OOM. Do you find that you are at the minimum threshold for regen and thus use your regen trinkets or are you still planing on dumping more regen for throughput as you progress?