Diablo III website has more on the changes coming to Diablo III in the upcoming version 2.3.0 patch for Blizzard's action/RPG sequel. This previews new loot, including three new sets, two reworked older sets, as well as new and updated legendary items for both the main game and the upcoming season 4. Here's a bit on sets:

We’ve added three new sets and updated two old ones! In Patch 2.3.0, you’ll be able to adorn your Crusader in the Seeker of the Light set, and unleash limitless Blessed Hammers upon your enemies after descending upon them with Falling Sword. The gods strike through your Monk’s Seven Sided Strike with Uliana’s Stratagem while turning your enemies into living weapons with Exploding Palm. The Spirit of Arachyr will let your Witch Doctor unleash the frightening potential of Hex and Corpse Spiders as they ensnare and poison those who stand before you.

Some of the older sets have been updated as well! For instance, you can revisit the Witch Doctor’s Helltooth Harness set to subjugate your foes with debilitating necrosis, or wield the unbridled power of Archon when your Wizard dons Vyr’s Amazing Arcana.