I just fought the queen and after trying to attack her over and over and the healers healing, I did something different. I STOPPED attacking the queen and stood outside her blast range. If a defiler came, I killed it and I let the archers first kill the healers (twice) and then the queen. I did no damage at all myself, but the archers took her out. Even if the defiler killed one or two of them before I could get to him, they were replaced within seconds. Also, the queen stopped using her blast since I wasn't in range. She just stood there and eventually died. SUPER SIMPLE.