Try to start with Slave Pens. I find it a bit easier, and a lot faster than mech.
It's pretty straight forward, but you will need at least 2 cc classes. It seems like one of your problems is here. Insist on bringing a mage and some other cc class. For slave pens, either hunters, rogues or locks are good.
That should leave you with 2 mobs most of the time. Usually i start with shield slamming skull (first dps target), then tabtarget and devastate on cross (2nd dps target). Thunder clap is horrible for threat, dont expect to keep mobs sticking, thats for sure. Then you just have to cycle between mobs with ss, dev and rev.
Your gear looks ok, but you need to replace those pvp items. Your avoidance isn't really all that great. I'd try to replace boots with the sha'tari wrought greaves first.
Also keep in mind that your dps'ers probably are decked in pvp gear and they deliver a lot of burst damage which can be difficult to aggro-manage (for the dps'ers, that is.).
Also, i'd look into respeccing to get anger management, and 5 points in deflection.
I am the spearhead. I am relentless. I am the last line of defense. I am a Warrior.