in case anyone with a paladin tank + 4 shaman group is looking for help on this... here is what I did and she was destroyed (regular mode, patch 3.0.2).

avengers shield pull while getting 2 lightning bolt casts, drop fire elemental totems and then just kite her around while your guys are on follow.

flame shock on every cooldown (or frost shock, your choice i suppose).

when the fire elementals that she casts stop to "pulsate fire" get in a lightning bolt cast or two.. the shocks and fire elementals really tore her a new one when i did it.

without the fire elementals a dragons breath ended up wiping me each time because my guys now stand there and her fire elementals kill em all.

hope it helps