A friend of mine, Firstaidspec from Blood Legion (US-Illidan) sent me an AddOn he had written for phase 3 Anub’arak. It displays the absolute health of all those in raid below 1500hp. Bind it to “Center Text 2″, and if you have anything bound to Center Icon, consider moving it to side icons with an addon similar to GridIndicatorSideIcons. Hopefully this, along with a [spell]Healing Stream Totem[/spell] and occaisional [spell]Holy Nova[/spell] will help you keep your healers alive during [spell]Leeching swarm[/spell].
You can download it here.