http://oi49.tinypic.com/2rqd9ad.jpg31k poh?? I find that number un-realistically low...
I don't know your trinkets, but are you taking into account things like jade spirit, trinket procs with intellect boost? All which scale higher with inner fire no less.
There you go, 31.8k without wep proc, 33k with weapon proc. You can see my ilev/intellect too. I dont have intellect procs trinkets, I dont especially like uncontrolled bursts of intellect that I might need in that particular moment or I might not. I prefer spirit procs trinkets, because I can always use the regen. Which, btw, works a bit different from 10 man to 25 man, as one of my new disc priest recruits recently told me (hes coming from a 10 man and said he needs to adjust to 25 man consumption because he went oom midfight).
As for group positioning - no bloody dps will care much about your poh in most fights. If the boss allows fair stacking, GG. If not, you can dream on about ppl arranging themselves according to groups. You can tell your rl to put melees in a group and ranged in another, but that's about it. And the addons dont tell you when 5 ppl are in range of some spell, they tell you when a spell is gonna heal over a set value. For all you know, it could be calculated on 2 ppl.
PoH: 13.5 k manaSo 5 of these will be close to if you had 2 stacks of DA up on the raid. Of course speaking of a 10 man setting.
5xPWS: 75k mana, considering one procs rapture, its still 60k mana. It's also about 5 seconds needed to cast them. I dunno what you do in your raids, but I dont have free time when I dont cast.
Also take into consideration: 10 man: 5xpws covers half of your raid. 25 man: it covers 20% of your raid.
Look, I'm not complaining about numbers. I was one of the ppl that considered the PoH buffs that we kept getting a poor fix to cover specc mechanic issues, and I always considered the 50% aegis a stupid un-needed buff that whoever came up with must have been drunk. I'm saying that ludicrous aegis has been driving disc into poh spam for ages (or aegis, if you want a bad pun).
I am however questioning the ppl saying : "stack crit and you're back on track". Shields need to be predictable and controllable to be useful. I'm repeating myself, but you cant control a crit. It looks good on meters, but its a bad healer stat, and its always been that. You cant tell your group "ops, sorry guys, I didn't crit. But hey, look, I'm awesome hps on the meter because I crit when you didn't really needed and I made the other healers overheal." We're not dps.