This is the final post on the diminishing returns from class stacking in a party or raid. If you have not read the first or second posts, please do so before reading this one.
Shaman: Along with the Paladin, the Shaman is a prime example of diminishing returns from class stacking in a party or raid. For clarification, this post will reflect the BC status of Shaman totems, which currently only affect the Shaman's party, and not the LK status of totems, which will affect the raid.
Like Paladins and their blessings, the first Shaman in a party will provide his or her group with the most valuable totems for the classes present. Thus, a second Shaman in the group will provide totems with the second highest value to the classes present, while a third Shaman will provide little additional value to the group. In addition to totems, each Shaman brings one Heroism/Bloodlust per ten minutes (one per fight except on long fights). Because the first Shaman will use his or her Heroism at the optimal time (Prince Phase 2, Lynx Phase 3, etc.) the second Shaman will use his or her Heroism at the second most optimal time because the buffs do not stack. Thus, Heroism suffers from diminishing returns if both Shamans are in the same party.
Elemental: While the Elemental only Totem of Wrath does stack with a second ToW, the casters in the party must be geared to take full advantage of the extra 6% to hit. If the present casters are pushed over the hit cap by the second ToW, then the second Shaman is providing diminishing returns.
Enhancement: Only one Enhancement Shaman per party brings additional utility via Enhancing Totems and Improved Weapon Totems. While a second Enhancement Shaman will increase the uptime of Unleashed Rage, one Shaman is sufficient for a high uptime and a second will suffer from a large reduction in utility.
Restoration: Only two Restoration Shamans per party bring additional utility via Restorative Totems, since both Healing Stream and Mana Spring totems can be dropped.
Warlock: Though Warlocks are a high dps class like Hunters, Mages, and Rogues, they also grant a surprising amount of utility to the raid via their unique abilities.
Only two Warlocks per raid bring additional utility via Curse of the Elements and Curse of Recklessness (not desirable on all bosses due to Attack Power increase), though additional Warlocks will bring increased DPS since they will be able to use Curse of Doom.
Only one Warlock per party will bring additional utility via their Imp's Blood Pact, though the Imp will obviously have to be out and withing range of the party members.
Affliction: Only one Affliction Warlock per raid brings additional utility via Malediction and Shadow Embrace (not all Affliction Warlocks take full 5/5 Shadow Embrace. Most take 1/5).
Demonology: Only one Demonology Warlock per raid brings additional utility via Improved Imp. This Warlock, however, will have to sacrifice their damage to keep an Imp out. In addition to this, some raid bosses can and should be tanked by a Demonology Warlock due to their high resistances and ranged threat output. I consider this nontraditional tanking to be additional utility, and thus only one Demonology Warlock per raid brings this utility.
Destruction: While additional Destruction Warlocks per raid will bring increased uptime for Improved Shadow Bolt, this suffers from diminishing returns.
Warrior: Like Warlocks, Warriors also provide a surprising amount of utility to their parties and raids. One Warrior per raid brings additional utility via Thuder Clap and Demoralizing Shout, which has synergies with Curse of Recklessness. Only two Warriors per party bring additional utility via Battle Shout and Commanding Shout.
Arms: Only one Arms Warrior per raid brings additional utility via Improved Thunder Clap. While more than one Arms Warrior will increase Blood Frenzy uptime, this is subject to diminishing returns.
Fury: Only one Fury Warrior per raid brings additional utility via Improved Demoralizing Shout. Two Fury Warriors per party can bring additional utility via Commanding Presence.
Well that's it for my series on diminishing marginal returns from class stacking in raids or parties. I hope that this has helped people learn about the value of properly building raid parties to maximize the dps, healing, and tanking abilities of all involved.
For the Horde and the Naaru!