Looking for an explanation (level 90 talents)

[Prentice]

Why would I take Execution Sentence over Holy Prism as a ret pally? Holy Prism deals more damage as well as heals allies. I have never really looked at Holy Prism before, but I'm definitely second-guessing the decision to blindly use Execution Sentence for the past.... forever.

Over the course of 60 seconds, you can use ES once and HP three times. ES deals 34,657 damage unbuffed. HP deals 11,716 each time cast for a total of 35,148 damage in addition to healing random party members for an equal amount.

Can someone please tell me what I'm missing? Does ES scale so much better with raid buffs? I never use ES on myself for the healing, so I'm not seeing the benefit there. Thank for your input.

EDIT: Perhaps the use of two additional GCDs every minute for nearly equal damage is the reason.

[Eace]

I'm thinking that it's the GCDs as well. Especially because Holy Prism doesn't generate any Holy Power.

[NickCageFanatic]

If you spec into Holy Prism you won't use it 3x a min because it's so low on the priority queue. Thus making ES superior.