Deep Arcane for PvP is reaaaally good. Doing damage while on the
move, bonus damage on snared targets etc etc.
Imagine no one's aiming you yet, you just stand outside taking
pot shots, and your barrage procs. 
Actually I think it's good for PvE too especially with the
instances all having to move around so much
Like in Occulus I could hardly DPS coz have to keep running
Made me wish I was Arcane spec again
But Arcane for PvP really nice sia.
I have to say that Hot Streak is quite sucky for Fire leh
The proc rate is SHIT
And I"m very sure of that coz I have all the animation and sound
to inform me when it procs so I never miss it!!!