Enhancement is a spec that has struggled with its tier bonuses in the past. Back in The Burning Crusade, we had such gems as tier 5's Your melee attacks have a chance to reduce the cast time of your next Healing Surge by 1.5 seconds, a bonus that provided absolutely no benefit to DPS beyond allowing us to live through a sticky situation. In Wrath of the Lich King, tier 8 gave us one of our best bonuses of all time: Increases the frequency of Maelstrom Weapon being triggered by your melee attacks by 20%. A patch later, tier 9 saw us unfortunately dropping that bonus for the overly boring and terribly mediocre An additional 3% chance to proc your Static Shock talent.
Cataclysm hasn't been significantly better so far. On the one hand, our current two-piece bonus is amazing. It gives us a 10% increase to Lava Lash, our hardest-hitting and highest-priority ability, as well as slightly buffing Stormstrike. At the same time, our four-piece bonus is 10% critical strike chance to just Lightning Bolt. This bonus isn't terrible in and of itself, but it's coupled with terrible itemization on both the legs and the chestpieces and bad itemization on the gloves. Most enhancement shaman will find best in slot is heroic tier 11 helm and shoulders, Heroic Tunic of Failed Experiments, Twilight Scale Leggings, and Heroic Proto-Handler's Gauntlets. Four-piece tier 11 need not apply.
Wednesday night, set bonuses for tier 12 were discovered on the 4.2 Public Test Realm. In an awesome twist, Blizzard themed all of the set bonuses around the raid they will drop in, the Firelands. Classes like death knights that don't already have fire spells to work with receive passive bonuses like Your critical strikes with melee abilities deal 15% additional damage as Fire damage over 4 sec. Specs like elemental, which already have fiery moves to work with, get set bonuses like Your offensive spells have a chance to reset the remaining cooldown on your Fire Elemental Totem, seamlessly weaving the theme of the raid with the class' abilities. Enhancement, which uses a surprising number of fire abilities itself, falls under this second category.