Divine Sacrifice

I'll try to explain this all.

The old (3.2) model of "raid wall" where you get to essentially Shield Wall your entire raid by bubbling to avoid the excessive damage was overpowered and we were increasingly starting to balance around it.

The new (PTR) model is that Diving Sacrifice applies to the party, not raid. It can absorb 40% of your health x your party size. If you are in a party of 5, it will redirect damage to you that is taken by the party up to a max of 200% of your health. If you are in a party of 2, it will redirect damage to you that is taken by the party up to a max of 80% of your health. If you take enough damage to drop you below 20% of your health, the spell is cancelled.

Divine Guardian reduces damage taken by the raid by 20% for up to 10 sec when you cast Divine Sacrifice. The damage reduction isn't directly related to the redirected damage any longer, except that it stops when Divine Sacrifice stops because you have absorbed too much damage or dropped your own health too low. (I understand the current PTR may not have DG stopping when DS stops.) The talent still affects Sacred Shield as a secondary effect.

Whether you bubble or not will not change the amount absorbed. If you do not bubble, then both DS and DG will cancel as soon as it drops you below 20%. We added this cap because we thought the self-gib feature of using DS / DG without bubbling was weird. However, the spell can still kill you if the damage is quick and massive enough. If you have DS up when a party member gets hit by a Mimiron rocket, you'll die before the 20% cancellation kicks in.

Example: Kallee the paladin has 50,000 health. She has the DG talent. When she uses DS in a full raid, she can absorb 20% of incoming damage to the raid until one of three things happen: 1) 10 sec expire, 2) she absorbs 100,000 damage total (from damage to her party only), 3) she drops below 10,000 health.

Yes, this means that in some situations you could get the full 15 sec duration if some part of the raid is taking damage but the paladin's party is not. The more typical case is a situation in which the whole raid is taking damage.

A related significant change is that all sources of damage should now count towards Divine Sacrifice. Before there were some situations, Twin Val'kyr for instance, where the paladin wouldn't take damage or wouldn't take enough damage from the redirection.

P. S. We have been trying to move more abilities from the party to the raid, but some just don't scale nicely and are either overpowered in a 5-player group or underpowered in a 25-player group. We may implement some kind of scaling mechanism for Cataclysm or just accept that a few abilities need to remain party only.

P. P. S. This has changed a couple of times on the PTR already and it's possible this is not the final implementation, so confusion is totally understandable.

IMPORTANT EDIT: Read the whole thread before responding. Later on I speculate that we might change this design.

Q u o t e:
I think the main complaint people have is that the current form encourages you to stick a paladin in a group by themselves so that you get the full length damage reduction on the whole raid, and also circumvents the risk of the paladin redirecting too much damage to themselves.

We tried to come up with situations where it would really be advantageous to sequester the paladin in this manner. You would have to make sure nobody in the paladin's group took damage (it does require at least one other person in the party) and even then all you're getting is 20% less damage for 10 sec. You could do it on Patchwerk I suppose, but you could put 4 people with the paladin and avoid damage from Patchwerk anyway. A lot of the other bosses do either raid-wide damage or strike random people so it's hard to keep the paladin from transferring any damage to themselves.

Put another way, it requires you to do more work and convoluted things to get a smaller benefit from the current "raid wall." While the latter was overpowered and could be game changing on a few specific encounters, it's not as if we see a lot of raids stacking paladins just for the DS + bubble option.

Q u o t e:
Paladin in a group with another healer on NRB after all fires are down. No other raid damage and raid wall goes up on tanks.

Paladin in a group with the MT for the heroic Jaraxxus encounter. Jaraxxus hits very lightly and mt takes no other significant damage.

Holy Paladin in a group with 1 other ranged on Anub'arak. Very predictable and light raid damage in P1 and 3.

But those are just situations where the DG ability is useful. Those situations don't seem to lead you to put the paladin in group 6 with one other person. You would need an encounter where say the melee were going to take massive damage while the paladin and their DS partner would be predictably safe.

Q u o t e:
Despite this, without a debuff to limit the number of times this can be used and the ability to make 8 groups, in a 25m raid I could see stacking paladins to effectively chain this an entire phase of a fight. Maybe 20% dmg reduction for nearly a minute in ICC isn't something you are planning to design around but I can almost guarantee raid leaders will be seriously looking at this ability as a means to gimp any phase where it's possible.

Then why don't you do that (stack paladins) now when you can mitigate 40% raid wide damage when you want (assuming a bubble)? I don't see how this change makes the ability more attractive.

After reviewing this some more, we will probably end up changing it again. For example, we're not sure we could solve the case of the paladin who sits in a party with 4 players who are in the raid, but don't zone into the instance.

We might very well iterate on this a bit, but we're thinking something like this:

Divine Sacrifice -- Works like it does on the PTR.

Divine Guardian -- When you use Divine Sacrifice, your entire raid also takes 20% less damage for 6 sec. The main difference would be that DG always stays active even if DS hits its damage cap or paladin health cap. The shorter duration would hopefully keep it as situational ("Here comes the big blast") and not something paladins try and keep up as much as they can.

Not set in stone... as if anything ever is. :)