So essentially Arcane Mages are pretty powerful right now or at least powerful enough that in the right situation they can be very smooth in PVP. Some people are openly QQing about it and calling for a nerf or re-balance similar to what happened with Ret paladins.
As Blue says in the post below, Arcane mages [...]

Arcane mages are insane fun right now (been fiddling with a friend’s not Nessaja’s) but it feels REALLY overpowered in PVP. The mana regen too with Mage Armor is something I wasn’t expecting.
Mage Armor OP?
For what it’s worth, Mage Armor is quite powerful, but it’s a trade-off. It’s going to make mages harder to kill [...]

Not much here but it’s worth posting.
Arcane Blast mana penalty lowered
We are going to lower the mana penalty after the first blast… but it’s possible you already have that change. (src)
Water Elemental not inheriting Master’s hit
We’ll check it out. (src)