Ok, sorry, I thought you know the issues but just didn't have time to work on them.
For Arcane I'll tell you from memories since I'm not specced arcane anymore:
1. Didn't use Arcane Blast, at all or at least not as a filler. Used Frostbolt.
2. Used Ice Lance or Fireblast instead of Arcane Barrage.
3. Movement as an arcane mage is important, since you don't have the control of frost. He should run back if the target closes in, blink if in melee range and use the mana shield (knockback glyph is a must)
For Fire I wasn't able to make it work. I've tried in PVP and using Lazyrider in heroics and he didn't pull. Even if I manually target he doesn't cast anything.