[Gringa]

We have all raid except for one or two healers do dps from the start and we ignore the panthers. Druids are feral, shamans are meleers and so on. Once she vanishes first time, we get healers back on healing duty. Waiting a little bit while collecting the panthers and then AoE them down. After that we spread out to wait for her return.
At this point we have the marked ones run around in the rooms, with mages frost novaing now and then. Priests shield the marked ones. Others still doing burst damage on her. Most of the times we get her before she vanishes a second time, otherwise she dies very soon after reappearing for the third beating. Basically though we ignore the panthers while dps:ing her, and aoe panthers when she is not around.

edit: ok, just checked the date on the post. guess noone has trouble with her anymore.