The Ancient city of the Qiraji is difficult and requires a good organization. Every class is needed: Druids entangling roots is needed for crowd control hand-to-hand with Mages' sheeping. All healers need to watch the tank at all times -- which can drop in a blink against Kurinnaxx's stackable-debuffs; and wear their mana-regen gear. Some of the fights with the first two bosses are very long. If you do not have mana regen gear, you will exhaust your healing before the bosses hit half health. That extra mana per tick can be the difference to keep your tank and team alive.