This is the continuation of the previous post on the diminishing returns from class stacking in a party or raid. If you have not read the first post, please do so here before reading this one.
Paladin: Paladins, along with Shamans, are some of the best examples of the diminishing returns granted by class stacking. Since the first Paladin in a party or raid should provide the blessing with the most benefit to each member, the second Paladin will have to provide the blessing with the second most benefit, and so on until all six blessings are being used. Any Paladin beyond a sixth will provide no utility from blessings, though the fifth and sixth Paladins grant almost zero utility anyway, since Sanctuary and Light are of little use to the dps and healers and Salv is detrimental to tanks.
Multiple Paladins can also provide multiple judgments on a boss, though a Retribution Paladin will be needed to keep up the Holy Paladin's judgments via Crusader Strike. As with Blessings, the first Paladin that joins the raid brings with him or herself the judgment with the most utility, while the second Paladin brings a less useful judgment and so on.
Holy: Only one Holy Paladin per raid brings addition utility, since only one is needed to give the relevant characters Improved Blessing of Wisdom. Most Holy Paladins also dip into the Protection tree for Blessing of Kings or the Retribution tree for Improved Blessing of Might. This gives up to three Holy Paladins additional utility if no other Paladins with these talents are present.
Protection: Only two Holy Paladins per raid bring additional utility, since only two are needed to grant Kings and Sanctuary to the relevant members of the raid.
Retribution: Only one Retribution Paladin per party brings additional utility via Improved Sanctity Aura. Only one Retribution Paladin per raid brings additional utility via Improved Blessing of Might and Improved Seal of the Crusader.
Priest: Just as in the main example of utility in my main post, only one Priest per raid brings extra utility via Power Word: Fortitude.
Discipline: Only one Discipline Priest per raid brings additional utility via Improved Fortitude, Divine Spirit, and Improved Divine Spirit.
Shadow: While a second Shadow priest per party will bring additional health and mana to the party, the amount granted by one Shadow priest should be more than sufficient. Thus, more than one Shadow priest per party brings almost no additional utility.
Rogue: Like their dps cousins the Hunters and Mages, Rogues offer little to no utility to the group. Their main use is the damage they output.
Subtluty: Only the Subtlety Rogue offers utility to his or her raid with Hemorrhage. More than one Subtlety Rogue per raid will improve Hemorrhage uptime, but the gains are diminished, similar to the Expose Weakness debuff.
As a personal aside, a Hemorrhage specced Rogue must weigh the loss of personal dps (by not going Combat) versus the gain to raid dps by taking Hemorrhage. Theory crafting has suggested that the gain to Rdps does not outweigh the loss to Pdps and thus Hemorrhage is not a viable spec for min/maxing.
I'll be back soon to finish up this series with the last three classes: the Shaman, the Warlock, and the Warrior.
For the Horde and the Naaru!