Spec your second paladin into (improved) Sanctity Aura for a HUGE threat boost for your tank (you'll have to put them in the same group though). You said a few times that threat was an issue for your warlock, so this could help you a lot. A possible talent build would be:
http://www.wowhead.com/?talent=sZV0tIx0dMgoxVfx0bcz
But there's a lot of room for change. I don't think you really need Precision on your offtank (although for the bear boss in ZA it's a great asset). Furthermore, I don't know if you use judgements, but the Improved Seal of the Crusader will add a lot of damage for all your casters as well.