You should be able to push 1000 tps quite easily at level 70 with paladin in blues. Not until you're maxed out in defense and uncrittable/crushable you start to worry about spelldamage and stamina. Before that 2-300 spelldamage will be plenty. With Avenging Wrath even my main can dps pretty hard without taking aggro from the tank.

On the second boss of Shattered Halls try this.

I would start the encounter slow. Judge Crusader and apply Seal of Righteousness. Dps him down to about 80% then just wait for the aggrowipe. When he runs for a new target, cast Avenger Shield on him, and BoP whichever target he chose. He should be heading back for you immediately. Activate Avenging Wrath and go to town.

Second boss of Shadow Lab is similar, with the added problem of the fact that you're oom after the first mind control phase. Pot mana and cast Avenger Shield when he becomes tankable after mind control, and dps hard. Positioning is key. Your dps need to be outside 30 yards to avoid the warstomp/knockback. Tank with your back to the wall (I favored the dirt patch to the left of the door, with my dps huddled together in the opposite corner by the door). Depending on the situation you may allow your dps to pull aggro after a warstomp, and range taunt him back, just to be able to do as much dps as possible in a short timeframe, but this can be very risky. Very hard encounter for pala tank.
That was really helpful. Up until now I would have to swap my 70 MS/Arm warrior with paladin for tanking the second boss in shattered hall. Once I get a spell sword, I'd try again with my pally tank.

For the second boss of shadow lab, that was whole new game. Biggest problem I have was with positioning after MC. My guys would eat the warstomp/knockback. After I heal back with priest, the priest would gain too much aggro and get pwned soon after that. and If I were to move my guys individually, I would spend too much time moving and when I am ready to DPS again, the next round of MC would start. Same story with Nazan's fireball in heoric rampart and Hydromancer Thespia's Lighting Cloud in heoric steamvault, I just couldn't dodge them in time. I guess more repair bills needed.