What raid heal should you cast?
First, let's talk about what a raid heal is. In short, it's the quick heal you throw on someone who's not the tank. It's mostly used when a healer or DPS takes incidental damage. Caught in AOE. Stands in the fire. Draws aggro from an add. Someone other than the tank has taken damage, and you need to fix it. This could apply to 25- or 10-man raids, or even 5-man groups.
The short TL;DR summary:
- Nothing beats Natures Swiftness + Healing Touch... except the 3min cooldown. High mana cost. Save for true emergencies.
- Rejuvenation + Swiftmend is your best go-to option, especially with the SM glyph. Just watch for the mana cost.
- Wild Growth is surprisingly good (but inefficient) for a single toon. It's a no-brainer if it will heal 2 or more toons.
- Rejuvenation beats Lifebloom as an instant-cast low-cost raid heal. But they're close. Use Lifebloom if you need those 2 fast ticks, if you might follow with a mini-stack, or if you're just about OOM.
- Regrowth is good for a toon that's low on health but unlikely to take more damage soon — say, a hunter who grabbed aggro but then Feigned.
- Nourish on the other hand has a niche for players on the brink of death. Use option #1 or 2 if they're available, but if not, turn to Nourish. Spammable — faster cast and more efficient than Regrowth.
Let's look at the numbers. For now I'm not going to worry about mana efficiency or whether your heal will be overwritten. (I'll have a bit to say about that later.) I just want to look what will heal the most.
Calculated based on Alamein's current spec, glyphs, and gear, and including the normal raid buffs I run with (in 10-man Normal raids, as these are what I spend most of my time on). I pushed these into Rawr to get the amount healed for each spell. Alamein is specced 14/0/57 for this analysis. Glyphs include both the Glyph of Swiftmend and the Glyph of Lifebloom.
I did not account for Haste. For these purposes, it means that the cast-time heals — Regrowth, Nourish, and Healing Touch — will land somewhat sooner, depending on how much haste you carry. I also did not account for Gift of the Earthmother. For this analysis it only affects the Rejuv+Swiftmend combo, enabling it to arrive .3 sec earlier.
If a heal can crit, I figured the average heal, based on % chance to crit and average values for a normal hit and a crit. I would have just used the normal values, but Improved Regrowth would make that a bit dishonest.
I did not assume any pre-existing HoTs on the target, which affects Nourish, Regrowth (due to the glyph) and Swiftmend.
Overall, I do not think these assumptions will affect the analysis significantly. The biggest affect comes from the glyph and talent that extend the duration of the HoTs, as well as the Swiftmend glyph.
Druid Raid Heals
(You can also see the full duration effects here, but really the first few seconds are the most important, right?) One set of heals are big but either have a cooldown or require standing still. In order of preference:
- Natures Swiftness + Healing Touch. 3m cooldown - save for real emergencies (usually on the tank). Chunky mana cost.
- Rejuvenation + Swiftmend. 15s cooldown. Really shines with the glyph. Use it whenever it's up.
- Regrowth or Nourish. Nourish is faster and more efficient in the short term — it's better to spam. Regrowth is the bigger heal and leaves the HoT behind.
- Healing Touch. Too slow for most situations.
But what about the more efficient spells? Surprisingly, Wild Growth wins for even a single target. It surprised me that it beat Rejuv and Lifebloom; you can see the effect here. Of course this isn't the most efficient use, but if more than one toon is damaged, it's a no-brainer.
The real tough comparison is Lifebloom versus Rejuvenation. They're both instant-cast, relatively efficient, and spammable. Which is best?
Raid Heals: Lifebloom vs. Rejuvenation
Lifebloom gets in faster, due to its 1-second tick. It leads in the 1-3s frame as a result. It also leads from 10-12s, after it blooms. (This happens earlier depending on glyphs and talents.)
Rejuvenation takes a couple seconds longer, but leads in the 3-5s and 6-10s frames, with 5-6s a virtual tie. It also regains the lead for good at 12s.
So overall, I argue that Rejuvenation is the better raid heal tool — but not by much. The faster LB ticks can be an advantage, and its mana cost is slightly lower. On the other hand, Rejuv can be Swiftmended later if necessary.
Oh, what about Tranquility? In 5-man groups, it rocks. Used at the right time, and when the healer won't get pushback or interrupts, it's a "do-over" for the group. In raids however it's tough to use, as it only hits your group.
Finally, a note about efficiency and overheal. My belief is that theorycrafters worry about these factors a bit too much. They are important solely because they affect whether the healer goes OOM. (If you had infinite mana, efficiency and overheal would be irrelevant.) It is important to know what's more efficient, and to use lower-cost spells when they'll get the job done. But when things are getting rough, it's more important to know what will give the most benefit.
Worrying about having your heals 'overwritten' is similar. Yes, your efficiency goes out the window if another healer drops a Flash Heal or something on top of your Rejuv, wasting the remaining ticks. But this only matters for the opportunity cost — you don't want two healers wasting GCDs on the same toon. That's not an effect of any particular spell; it's about communication and working well with your partner. Beyond that, it's about efficiency — see above — and healing meters. And if you're watching the healing meters that closely, your raid will suffer from it.