Just as a side note, an Elemental Shaman who drops a full totem spread is running around pretty much fully raidbuffed.
The things that they also get benefit from are:
Blessing of Kings & +Int mage buff - more crit and mana regeneration
Misery or Improved Faerie Fire - 3% hit buff
Earth and Moon, Curse of Elements or Ebon Plague +13% spell damage buff to target
Everything else they bring themselves.
This means that their dps actually doesn't go up hugely (Curse of Elements/Ebon Plague/Earth and Moon notwithstanding) in 25-man vs 10-man vs 5-man vs questing.