I started off enchanting my weapon with Deathfrost, but later learned that the MOP enchant Elemental Force also worked as frost damage for freezing the boss and does way more damage (more damage means getting him to <5% faster, meaning you only have to shatter him once) so I stuck with that. Then you should make sure you have a fast one-hander on standby (I used my healing mace with a speed of 1.9) enchanted with Windsong for the haste proc. Depending on your gear (as you can see I'm mostly greens and low blues) you might have to enchant, gem, and reforge into as much haste as possible, and use a haste elixir and haste food. Finally, I recommend the Holy Avenger talent.
After that setup, just make your way to the boss (all the others on the way are pretty faceroll) and engage. Pop all your CD's except for Holy Avenger to burst him down to as low health as possible before he freezes to minimize shatters. Once you get the second message saying he's freezing up, build up to maximum Holy Power and white damage for a while. As soon has he's frozen solid, switch to your fast one-hander, get behind him, pop Holy Avenger and any haste ability you might have (Alchemy CD, for example) and spam Crusader Strike and Templar's Verdict. He should go down easily.
This same strategy should work perfectly with rogues, warriors, and monks as well. Happy pet farming!