Having multiple dedicated healers in a PvP situation really makes the difference. I just learned that in Gurubashi arena and it lead to someone reporting.
I had 3 dps(a hunter to see who was coming, a mage and a shaman), a priest healer and a druid healer. Both healers firing off their emergency AoE group heal was just epic: It looked like my team was invulnerable for 10 seconds or so
For any PvP situation in the future, I'll just bring 2 dedicated healers and 3 dedicated DPS.