Diablo 3 patch 2.2, coming soon to the Public Test Realm, will add new Legendary level 70 armour sets as well as redesign existing ones.
The new sets are Unhallowed Essence, Wrath of the Wastes, and Delsere's Magnum Opus, which appears to be missing a chest piece. In order they appear to be for the Demon Hunter, Barbarian and then Wizard character classes.
The Battle.net blurb previewing the patch mentioned you will "literally" take the Wrath of the Wastes armour for a spin. That makes me think it has bonuses to the Barbarian's Whirlwind ability.
"In addition, we're redesigning - and, in some cases, adding - bonuses to existing Sets like Zunimassa's Haunt, Raiment of a Thousand Storms, Roland's Legacy, Tal Rasha's Elements, Inna's Mantra, Natalya's Vengeance, and Immortal King's Call. This means a grand total of 10 new or revamped play styles to try out!"
Patch 2.2 will also add 15 new Legendary item powers to the game. The examples given are a Barbarian's boots causing the ability Avalanche every time you use the ability Ground Stomp; and a Demon Hunter's gloves causing Rain of Vengeance to deal a massive 84 per cent increased damage.
Increased ability damage is a statistic you see written in purple on items already but not, as far as I can remember, in the Legendary power slot. It has never scaled as high as in the Demon-Hunter-glove example above, either.
Blizzard is adding new Nephalem Rift areas/tilesets to freshen up the farming experience, and also 14 new Exploration bounties to revitalise Adventure mode.
New types of Treasure Goblin are on their way, in the shape of a blue Gelatinous Sire that splits into smaller goblins; a golden Gilded Baron that "helps satisfy your never-ending greed for gold"; and the red-legged Insufferable Miscreant who comes with friends. It's not exactly clear what their loot will be, other than the hint at gold.
An under-the-hood but potentially important change in patch 2.2 will be the swapping of game file types from MPQ to CASC - Blizzard's proprietary system.
"This new file format has lots of improvements that directly benefit players, including a self-maintaining file structure (which helps prevent errors during installation), a faster and more reliable patching process, the ability to hotfix game client data, and a whole lot more!"
All existing game installations will need converting to the new file type when patch 2.2 goes live, so potentially a large download. Console versions are unaffected by this change.
Class changes are sidelined in this patch for the new Legendary powers on items, although PTR testing may result in a few changes. There's also a new cosmetics window that will, at a click, let you use any just-for-looks items. The benefit of this is that they won't sit in your inventory and take up valuable loot space.