Blizzard shared some more information on the class tier sets as well as the recent changes from the new PTR build.

Class Sets (Source)

I’d like to share some clarifications of some details of how the set bonuses work as well as some revisions we’ve made. Your feedback has been very valuable, thank you. We’re continuing to work on and tune these bonuses, and we’ll share more updates as we make more changes.

First, a couple functionality clarifications:

Vengeance Demon Hunter: Fiery Brands applied by the (4) Set Bonus will gain the benefits of Revel in Pain, Charred Flesh, and Fiery Demise. Burning Alive will cause the Fiery Brand it applies to spread just like a directly cast Fiery Brand.

Arcane Mage: Mana spent on Arcane Surge counts for the (4) Set Bonus. The tooltip has been updated to reflect this.

Updated Bonuses

Survival Hunter (4) Set Bonus: Every 25 Focus spent reduces the cooldown of Wildfire Bomb by 1.0 sec, and the target of your latest Kill Command takes 100% increased damage from Wildfire Bomb for 8 sec.

Fire Mage (4) Set Bonus: When your direct damage spells hit an enemy affected by Charring Embers 20 times the damage of your next 2 Phoenix Flames is increased by 200% and they refund a charge on use.

Frost Mage:

(2) Set Bonus: Flurry and Ice Lance damage increased by 10%. Flurry causes an explosion on impact, dealing 50% of its damage to nearby enemies, damage reduced beyond 5 targets.

(4) Set Bonus: Casting Ice Lance on a frozen target has a 10% chance to trigger Brain Freeze.

Brewmaster Monk (4) Set Bonus: Rising Sun Kick grants a stack of Elusive Brawler, and when you dodge, the damage and critical strike chance of your next Spinning Crane Kick or Rising Sun Kick is increased by 5%, stacking up to 5 times.

Developers’ Note: Developer’s Note: This change is not in for this week’s PTR, but will be added in a future PTR build.

Windwalker Monk (4) Set Bonus: Your melee auto-attacks have a chance to launch a Shadowflame spirit at your enemy that duplicates your abilities at 20% effectiveness for the next 7.5 sec.

Enhancement Shaman (4) Set Bonus: Sundering increases your Physical and Fire damage dealt by 30% for 15 sec and your next 3 Chain Lightning casts deal 100% increased damage and refund 50% of Maelstrom Weapon stacks consumed.

Demonology Warlock (4) Set Bonus: Grimoire: Felguard deals 20% additional damage. While Grimoire: Felguard is active, your demons deal 20% additional damage.

Tuning Updates

Mistweaver Monk (2) Set Bonus: Soulfang Infusion restores 5% of your maximum Mana over 5 sec (down from 6 sec).

Windwalker Monk (2) Set Bonus: Rising Sun Kick deals 15% increased damage and has a 30% chance to go nova, dealing (300% of Attack Power) Fire damage to all enemies within 8 yds.

Enhancement Shaman (2) Set Bonus: Sundering increases your Mastery by 24% for 15 sec. (up from 12%)

Demonology Warlock (4) Set Bonus: Grimoire: Felguard damage bonus reduced to 20% (down from 40%).

Arms Warrior (2) Set Bonus: Chance to critically strike and critical strike damage reduced to 5% (from 10%).

Protection Warrior:

(2) Set Bonus: Shield Slam now reduces the cooldown of Last Stand by 1 sec (up from 0.5).

(4) Set Bonus: The wave will deal 45% of Attack Power.