honestly if your pulling 9-12k tps you cant really do much more on your end. You are even running arp and haste gear. Besides a possible hodir trick initial threat boost, the 2 pallys can help you out with salv. Disc can burn pain suppression, to off set some of the burst threat. With no rogue or hunter its going to have to be a combo of you doing everything u can while they help you out.
If you aren't familiar with the hodir trick. Have the mage threat cap then pop images, Mage burns all cooldowns to push threat as high as they can. Timing is important , but one taunt just as images fade should get you ahead at least a bit. Mage can then invsi if they want, as least in theory the mage should be one less to worry about for the rest of the fight.
A faster base speed weapon perhaps for more Maulin?
Hope this helps , and if it doesnt at least be reassured your doing plenty of tps =P