Blizzard have updated the patch 10.1 day 1 class tuning pass with some additional changes for Arcane Mages. You can find the full list of changes here. 

Tuning (Source)

We’ve added some Arcane Mage tuning to tomorrow’s updates.

Mage

Arcane

Vault of the Incarnates 2-Set bonus Arcane Blast now provides 3% critical strike chance per Arcane Charge (was 5%).

Arcane Blast damage increased by 4%.

Arcane Missiles damage increased by 5%.

Developers’ notes: Heading into the Embers of Neltharion patch, Arcane’s 2-piece bonus from Vault of the Incarnates is performing better than intended.