I think the validity of this thread lies not in "how to do sarth +3 10 man" but "who is the best choice for speccing into x buff/debuff"
Does that ISB Lock > Scorch + Totem of Wrath depend on having more than 1 warlock, or a specific number of mages, or is it simply "If you have a mage, a warlock, and an elemental shaman, then the warlock should be Demonology/Destro spec to provide ISB and Demonic Pact so the mage doesn't have to scorch and the shaman can drop flametongue"?
I've always used
MMO-Champion RaidComp to try balancing raid buffs/debuffs when forming 10 mans and tried to mix both maximizing buffs/debuffs and taking players that need the achievement. With my fairly caster heavy guild, it's often been tough fitting in a 3rd melee for achievement attempts.
A lot of answers to your question become a simple matter of who you have. At the moment I don't have an Enh Shaman, so Agi/Str and +10% AP are almost always coming from my DK.
Simply going down the list and trying to think logically about opportunity cost in terms of both time and talent points:
Buffs:
Agi/Str: Enhance Shaman (Easily improved making it better than Horn)
Armor %: Holy Priest (Shamans have more/other talents worth taking)
Attack Power: Retribution Paladin (Warriors can opt for Unleashed Rage talent, or apply Commanding Shout, also have to reapply midfight)
Attack Power %: Blood Death Knight (Lower talent cost, also increases personal DPS)
Damage %: Retribution Paladin
Damage Reduction %: Protection Paladin (Works on multiple Targets)
Haste %: Moonkin (required talent) or Retribution Paladin (nothing else to spend points on really)
Healing Received: Restoration Druid or Protection Paladin (Both will take the talent anyway)
Health: Warrior (Unimproved version superior to warlock alternative, Paladins providing other Shout)
Intellect: Mage (Superior)
Melee Crit: Feral Druid (Required talent)
Melee Haste: Frost Death Knight (Required Frost DPS talent)
Replenishment: Shadow Priest and/or Retribution Paladin (required talents)
Spell Crit: Moonkin Druid or Elemental Shaman (required talents)
Spell Power: Demonology Warlock (Better than Totem of Wrath at higher gear levels, allows Shaman to use Searing?)
Spirit: Priest
Debuffs:
Armor (major): Protection Warrior (applied in normal rotation)
Armor (minor): Feral Druid (Free to apply)
Attack Power: I don't know.
Bleed Damage: Feral Druid (Required talent for tank specs)
Cast Speed Slow: Probably Rogue (Mages won't be arcane?, Warlocks Curse of Agony)
Crit Chance: Retribution Paladin
Healing: I don't know. Probably Rogue depending on Marksman Hunter viability.
Melee Attack Speed Slow: Protection Warrior or Death Knight (Part of Normal rotation, Protection Paladins and Feral Druids have other necessary talents)
Melee Hit Chance: Probably Hunter (Moonkin glyph removes the hit reduction but may not be required in 3.1)
Physical Vulnerability: Rogue
Spell Crit Chance: Apparently Demonology Warlock
Spell Damage Taken: Moonkin or Unholy Death Knight (Required talents, free to apply)
Spell Hit: Shadow Priest (Required talent, free to apply)