There are many better options. The heal proc would need to be modified by sp and proc very frequently to make up the difference.

Just as an example, [Solace of the Defeated] + [Sif's Remembrance] is 28 more passive sp and over 2x the mana regen than Onyxia's 25m set.

Renew is better than flash heal if the raid is taking continuous damage or if you have to move a lot. A typical flash heal is around 6k, so you only need 3 renew ticks for the two spells to break even and 4 for renew to be better. Being able to heal while moving is extremely important on a number of fights.

Can you clarify your random string of abbreviations, or better yet just link to the build you had in mind? I've been trying a full throughput focused holy spec largely because mana feels like a non-issue right now. I have yet to see how it holds up on longer fights though.

Blessed Resilience + Test of Faith + Empowered Healing, -Healing Prayers, -Inner Focus, 1/3 Empowered Renew

I imagine it looks something like this

More or less: http://talent.mmo-champion.com/?prie...HVdzbUe,,10482

Question remains - why Int stacking than SP/Haste?

Worth mentioning the ilvl 245 trinkets pair up to: 250 spellpower, 96 mp5, 576 hp5 (lol? i guess it's useful on Anub'arak...) and of course Cauterizing Heal ~ 2500 (which I think is useless, but anyways).

Many of the top priests I've armoried were full of Intellect gems and usually Intellect trinkets, rocking up to 30k mana (depending on spec ofc).

I used Intellect in Ulduar, but with ToC-25 gear, I have so much more Intellect/Spirit, I am going Spellpower now. It could be the priests you are armorying haven't updated their gems/gear yet. ilvl 245 and 258 are such huge gains in stats. It's almost insanity.

You should not be spamming heavily on Twin Valkyrs heroic. Aside from the tanks, the damage is incredibly predictable and easily healed with HoTs and the occasional Chain Heal.

If your raid is taking much heavier damage than this, then you need to consider a strat change.

I certainly wouldn't recommend stacking int over spellpower, but gemming for int over haste or crit in a yellow socket is a simple and effective way for those of us who are switching between the two healing specs to gem tier pieces, etc. for both Holy and Discipline.

For disc, because the disc soft cap for haste is so low, haste gems aren't desirable. For holy, I've been able to make up the difference in haste between T8 and T9 with offset items, so again, no need for haste gems. Now that I've picked up a decent amount of ToC gear, my raid-buffed crit is already nearing the point of diminishing returns as Holy and I'm already past that point in my disc spec, so there's really no need to gem for crit either. All this considered, intellect isn't really such an unattractive stat for a yellow socket, and the extra mana has come in handy on progression nights.

Renew is probably better than you think it is. From a couple pages back:

Rejuvenation is the clear winner here obviously, but we aren't druids, HoTs are not our "niche." But I think you'll see that there is comparable throughput between Renew and Rejuv, granted you invest in it and mana efficiency is not an issue for you. Renew has consistently been in my top three healing spells, it's a very viable healing tool.

I still use Flash Heal quite a bit on some fights (noticed I was using it a lot tonight on Heroic Jord Jaraxxus.25 while spot healing and healing Incinerate Flesh) but in general it's more my go-to for a reactive heal or a heal that's needed *now*. I usually toss up Renew on someone who will be taking predictable damage. That sounds sort of elementary but I do find they fulfill two different niches for me. Regardless, I don't think anyone glyphs for Flash Heal in T9 as mana isn't really an issue anymore in ToC gear, so that can't really be used to argue for using it vs. Renew. Surge of Light is a good argument, however.

Even if you consider not needing much haste as Disc, therefore stacking Int for dual spec, it still doesn't change the fact that Spell Power would be better in general.

But some of those priests had like 700+ haste to begin with :P, which is clearly an overkill for Disc.

I'm just trying to understand if there's a super challenging encounter where you need up to 30k mana, which you can't progress with your stacked spell power. Or is it just a preference, as good as other options.

As for renew, I agree with its usability and I've always liked it.
The only thing that bothers me is Renew not proccing Inspiration or Serendipity, while Flash Heal procs everything.