I run with no frost res gear now at 30% it just holds you back, 4 piece t10, heroic scarab and sindra trinket. Don't forget an armor pot in p3. Use a cooldown when switching and be mindful of what your assigned healers are calling out, if they can't heal you ect. keep her debuffed up but don't go nuts attacking her as you will just build unwanted stacks and threat should be well ahead of the dps anyway.
Marking targets, coordinating CC, and *most importantly*, pulling responsibly so that 9 elites didn't rush us and wipe the party, this Is something I have missed since nov 08.