Expansion Leatherworking

[Tuftears]

Don't take these as fact but this is what I've heard:

Apparently these are the druid set bonuses.

Moonglade Raiment
2 - Your Rejuvenation spell now also grants 70 dodge rating.
4 - Your Bear Form, Dire Bear Form, Cat Form, Travel Form, Aquatic Form, Moonkin Form, Tree of Life Form, and Flight Form spells cost 25% less mana.

Malorne Raiment
2 - Your helpful spells have a chance to restore up to 120 mana.
4 - Reduces the cooldown on your Nature's Swiftness ability by 24 sec.

Malorne Regalia
2 - Your harmful spells have a chance to restore up to 120 mana.
4 - Reduces the cooldown on your Innervate ability by 48 sec.

Malorne Harness
2 - Your melee attacks in Bear Form and Dire Bear Form have a chance to generate 10 additional rage.
2 - Your melee attacks in Cat Form have a chance to generate 20 additional energy.
4 - Increases your armor by 1400 in Bear Form and Dire Bear Form.
4 - ncreases your strength by 30 in Cat Form.

Nordrassil Harness
2 - When you shift out of Bear Form, Dire Bear Form, or Cat Form, your next Regrowth spell takes 2 fewer sec. to cast.
4 - Your Shred ability deals an additional 75 damage, and your Lacerate ability does an additional 15 per application.

Nordrassil Raiment
2 - Increases the duration of your Regrowth spell by 6 sec.
4 - Increases the final amount healed by your Lifebloom spell by 150.

Nordrassil Regalia
2 - When you shift out of Moonkin Form, your next Regrowth spell costs 450 less mana.
4 - Increases your Starfire damage against targets afflicted with Moonfire or Insect Swarm by 10%.

That would seem to indicate that the 5-piece T4 sets only require you to wear 4 of the 5 pieces. Which would mean you could get both the 3/3 Windhawk set bonus and the 4/4 Druid T4 bonus - pretty shiny, IMO.