WHM - Cure III vs. Medica

[Kelya]

I use Cure 3 when A) everyone is close enough and B) their HP is really low.

This.

Don't forget each AOE spell has different healing values. (Medica 1 ~ 1050 / Cure 3 ~ 2050 / Medica 2 ~ 2550 at ilvl124)

If the damages are very less than what provides a Cure 3, you should not Cure 3 just because ppl are stacked. In few situations though, it can be an important factor, as much as if it's a proc. But in most of the cases, stacked or not you will Medica 1 for less damages, Medica 2 for more damages. Also if less than 5 ppl got hit and you are NOT forced to top them fast, you should NOT AOE heal them, no Cure 3, no Medica, just some Cure 1/Regen and there is another healer so you can easily share the tasks and heal 2 persons while he's taking care of the 2 others.