I'd say Aluriel, since its easily 5 healable (with the nerf to her health and buff to dps's output with new traits).
Not sure if your group has the dps to 4heal Krosus at the moment but spellblade shouldnt be hard to dps through even with the extra healer.
The extra healer makes frost phase much easier and makes it so that mistakes are easily dealt with. extra raid cooldowns help as well.