Recently I've wondering a few things (as a priest specifically)

How much aggro will a PW:S generate? Does overhealing of Renew/Rejuv count? How many points of healing does it take to overcome say, a Sunder when the tank has Defiance?

There are probably other things I'm not thinking of atm, but that's good for starters.

1. PW:S generates threat equal to 50% of the heal amount.

2. AFAIK overhealing, even on HoTs, does not generate any threat.

3. There's an aggro generating thread on the Warrior forums somewhere.

As I recall a normal heal causes 0.5 threat per point healed, overheals not being considered. (1:2 threat:heal)
HoTs don't even really have overheal anyways as they effectively stop ticking once the target is at full health. Its why druids/priests can manipulate any healing chart (even effective healing) so easily - throw enough HoTs out with 0% overheal and suddenly it looks like you are a god among healing classes.

HoTs still generate a small amount amount of overheal, nothing compared to a basic heal though. If your renew ticks for 400, and your target is missing 600 health, it's going to heal him for 800 total - the last tick that heals him to full still heals for the full amount, regardless of whether he's missing 200 health or 5. Granted, the overheal doesn't generate any threat, but it does have a very minimal effect on meters =p

PW:S generates 1/4th the aggro of the damage it would shield against. So if your PW:S protects against 1,000 damage by casting it you generate 250 aggro.

That's not true, watch your combat log the next time that scenario occurs. The first tick will be for 400 and the second one will be for 200.

Hrmm you appear to be right. When did that get changed..... I could have sworn the second tick used to only heal for the amount required.

Yeah, I'm 99% sure that it used to be like that, and I'm not entirely sure when it was even changed :p It just works a little different now.

Yeah, that's a ninja change for sure. It did work like that, just got changed - no idea why though, it was fine before?

Does anybody seriously have a problem with healer aggro? It has never been an issue that I can remember. Even on Broodlord which used to be sensitive it was always a mage with their lack of an aggro dump who risked pulling aggro if the fight went on for too long.

The only fights which seem to be sensitive to healer aggro are more recent ones in aq that have mobs that do constant de-aggro of the tanks. Even then I've never worried much about Subtlety or other talents. The reality is when the mob de-aggro's the tank chances are very good they are going to come after a healer because we are the ones with the aoe aggro generation. So even if I could get 50% off my personal aggro generation, it just means they are going to go to the next healer on the list. Either case if a tank isn't there to pick it up or if I can't go bear in time, it means a dead healer. I dropped Subtlety from my talent tree ages ago and never saw much reason to pick it up again.

The only other aggro-sensitive moves are things like NS+HT on a pull. And I just put that down to healer stupidity. 10% off aggro generation isn't likely to save you there.

Hmm, there goes my little secret for lowering overheal %. When did Blizzard ninja change this? 0o

:*(

I've pulled aggro on caster emp via healing (we use warriors to tank them.)

And yes I have full subtlety as a priest.

tell the other healers on your side to stop slacking.

Fearing the defenders? O_o .... don't you mean the warriors?

Yeah when I saw the new Shaman talent tree at first I thought the threat reduction looked nice. Then I realized there are very few occasions that I am going to pull heal aggro to begin with. Namely on defenders when we get a thunderclap/meteor and raid mana is at a premium its rough when priests either die in the pull or don't have the mana to fear ... chain heals seem to draw better aggro.

Other than that I'll pick up scarabs on a mindslayer pack or ouro. Or sometimes an unlucky fear gives me a champion.

Though I do have sudltey on my cloak ... only because theres really nothing else worthwhile to put on it. I'd gladly trade it it for some +healing or even 100 mana.

+5 resist all is a cheap versatile enchant to put on healer cloak.

+70 armor isn't the worst thing in the world either, imo usually if resist gear is needed having a resist cloak is likely - with the new patch both nature resist and frost resist cloaks are craftable - so I don't really think +5 resist all is necessarily all that great, but then neither is that much else in the way of cloak enchants for casters.

Helps what though? Helps the next healer in line get aggro instead? Not much help, that.

A couple of weeks ago I was running late into BWL. I ran into some trouble along the way and popped NS and HW as I ran for the orb. Or atleast I thought I hit HW. I was unaware that NS was still up as we engaged Firemaw.....

I can't tell "how much" it helps, but I can say I've noticed a difference once I got the enchant on my cloak.

The only fight I've ever seen a problem with healing aggro is what seems to be a problem with the Emps encounter. We've had healers on the opposite side of the room (on the caster side) somehow pull the aggro of the melee emperor halfway through the teleport cycle (sunders, demo shout all piled on, and DPS was well under way), and well into the fight. But that seems like a buggy situation, not someone actually overcoming the tank's threat.