One tip for Mage pulling aggro, use Mirror Image. It makes you not earn ANY threat while its up, and it boosts your DPS. Invisibility also is an aggro dump.

Also, since it appears your tank is pretty well equipped now, you might find that you dont need much healing. I've started making my priest spam smite, just so she doesn't sit there. She does 1400 dps just by doing that (with holy fire thrown in) I start the fight by throwing PW:S, renew, and PoM on my pally, and for most pulls thats all i need. With your boomkin, you could probably make a "pre pull" macro, that uses the priest and boomkin to HoT up the pally, then go back to boomkin form. You do have to watch for healing aggro using this tactic, make sure consecrate is down, and have that taunt button ready.