Yo,
Blizz releases some numbers for T21 sens:
Fire set bonus looks OP as hell. Frost is Decent(?). Arcane needs further investigation. If you can stack the 2pc buff it may be stronk.Item - Mage T21 Arcane 2P Bonus - Spending Arcane Charge Buffs Damage Each Arcane Charge you spend increases your damage dealt by 0% for 0 sec. 2% for 8 sec.
Item - Mage T21 Arcane 4P Bonus - Generating Arcane Charge Grants Haste When you generate an Arcane Charge, you have a 0% 4% chance to increase your haste by 0% for 0 sec. 20% for 6 sec.
Item - Mage T21 Fire 2P Bonus - Combustion Duration Increases the duration of Combustion by 0 sec. 2.0 sec.
Item - Mage T21 Fire 4P Bonus - Combustion Increases Crit Damage Combustion also increases your critical strike damage by 0% for its duration. 50% for 14 sec.
Item - Mage T21 Frost 2P Bonus - Flurry Damage Each successive ice bolt of a Flurry deals 0% more damage. cast of Flurry deals 25% more damage.
Item - Mage T21 Frost 4P Bonus - Brain Freeze Buffs Frostbolt When you consume Brain Freeze, the damage of your next Frostbolt is increased by 0%. 75%.
What do you think about them?
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arcane set is crap...