Your stat order on a one-minute single-boss fight, in Attack power: crit 25.1 per 1 %, attack speed 19.3 and spell hit 17.4.

Point for point, expertise leads at 3.75. Intellect is worth 1.89, Strength 2.20, spell damage 1.30 and Agility 1.40. The benchmark set is the base for every weight.

Hit

Against a raid boss, 9 % hit is the melee cap: you miss 8 % before hit, and your first point of gear hit buys nothing against a boss three levels up. A two-hander has no dual-wield penalty, so that 9 % caps your white swings, Stormstrike and the Windfury attacks alike. This set already has 9.0 %, and once you reach 9 % more melee hit is worth nothing, which is why the table leaves it out on fights whose set is there.

Your spells are another matter. They miss 17 % of the time before hit and stop at 16 %, so they still miss after your weapon is capped. In Forever, hit on gear counts for your spells as well as your weapon. Past 9 %, an item's 1 % hit is therefore worth the Spell hit weight, 17.4. All of these caps are Classic's numbers, since Forever's own tables aren't out.

Crit

Melee crit starts Flurry after every crit, from your swings, Stormstrike or Windfury. Spell crit lights Elemental Devastation, 9 % more melee crit for 10 seconds. Crit on gear counts for both, so an item's 1 % crit is worth Crit plus Spell crit: 25.1 and 10.7 here. White swings stop gaining from crit at about 60 % on your character sheet, far above this set's 28.2 %.

Intellect, Strength and Agility

Intellect is a damage stat for an Enhancement Shaman in Forever. Mental Dexterity turns all of it into attack power, Mental Quickness turns 30 % of it into spell damage, and Ancestral Knowledge adds 10 % more Intellect. It also gives mana and spell crit. That puts it above Strength on every fight but a single boss for one minute, where the mana never runs short.

Strength converts at 2 attack power, and Blessing of Kings lifts it 10 %, hence its 2.2. Agility gives a Shaman crit, 1 % per about 20, and no attack power, so its weight follows crit's.

Spell damage

Spell damage reaches Fire Nova, both shocks, Lightning Bolt, your Searing Totem and Dragonbreath Chili. It is worth 1.30 a point on a one-minute single-boss fight and 2.24 against three bosses, where Fire Nova does a third of your damage. Nature damage only reaches Earth Shock and Lightning Bolt, so it is worth less: 0.59.

Attack speed and expertise

Attack speed adds swings, and every swing rolls for Windfury Weapon, Flurry's crits and Maelstrom Weapon stacks. A point of expertise is worth 3.75. 10 expertise is 1 % less dodge, out of the boss's 6.5 %. Behind the boss there is no parry or block, so dodge is all it trims. Adaptive Combat Assistant, a trinket with 2 %, is one of the few pre-raid items that carry it.

Weapon damage

Weapon DPS is worth 13.6 Attack power for each point your two-hander carries. White swings, Stormstrike and both Windfury attacks all roll your weapon's damage first.

On every fight

Against three bosses spell hit and spell damage about double, because Fire Nova hits all three. On a single boss crit, attack speed and spell hit stay close, so take whichever an item gives most of.