In 4.1 There will be some quite substantial changes to Arcane mages.

Arcane Blast damage has been increased by 13%. In addition, the stacking effect of Arcane Blast now increases the damage done by Arcane Explosion, and Arcane Explosion does not consume that effect.
Arcane Explosion damage has been increased by 13%.
Arcane Missiles damage has been increased by 13%.
Blizzard damage has been increased by 70%.
Talent Specializations
Arcane
Arcane Barrage damage has been increased by 13%.

Fire
Combustion no longer has a global cooldown.
Ignite is no longer triggered from periodic critical effects.

Frost
The root effect from Shattered Barrier now shares diminishing returns with the root from Improved Cone of Cold.

The increase on Arcane blast will make Arcane blast to give you a 65% damage increase with 4 stacks from 52%. This will be a very helpful increase and will hopefully make arcane mages a more formidable specc to play Along with the buff so Arcane Barrage, Missiles and Explosion buffs.

Also the 70% increase on Blizzard will hpefully make it not the worst aoe to use anymore :L