Just coming on here to get some opinions...
My guild is now 7/7 normal and looking to start on the HMs in Firelands (& also to keep working through the T11 Heroics that we haven't done yet)
Our healing setup is Holy Pala, Resto Druid & Holy Priest but it feels more and more as though shields/barrier might do more for us - i.e. we're considering getting our priest to spec Disc. Her having 2 healing specs isn't really viable, however, as for many reasons her Shadow Spec isn't something we/she would like to lose.
So... If she went disc would this cause us issues anywhere? Our resto druid is decent and is pushing very decent numbers on all fights, but I still do have concerns about losing the extra throughput (& Lightwell <3 <3 <3).
So, to those of you with the same 3 classes of healers as us, what do you do?
Yeah honestly, being both holy and disc is the best possible decision, on specific encounters disc is better than holy and on specific encounters holy is better than disc. In general, whatever the player is best at is what the player should play.
Depending on how hard you push, you may very well need to alternate between holy and disc for different fights.
Disc is awesome for rapeface, and provides strong cooldownss for Majordomo etc. Certain mechanics just get alot easier to deal with with a discipline priest in the group.
Having that said, holy isnt bad either, and in the end i think your going to swap around.
If shes raiding as a healer, she should dual spec both tbh. If shes the person going DPS, on 2heal fights, well then start memorising specs, glyphs, and keybinds, your gonna respec alot.
My group is 1/7 Heroic Firelands and I have healed most the encounters as both specs. The other two healers are also a Paladin and Druid.
Heroic Shannox - I usually heal the rageface targets, Disc is almost required in this role.
Lord Rhyolith - I prefer Holy on this encounter but you can always have your Priest DPS this one as two healers is preferred anyways.
Beth - Another one I prefer Holy but Disc is viable and offers Barrier for the last phase.
Alysrazor - Again I prefer Holy but with guaranteeing your Priest can get at least one feather Disc will do well
Bal - Disc is preferred
Staghelm - I lean towards Disc for Barrier since we push a couple extra Flame Scythes rolling raid cooldowns.
Rags - Holy made the fight a lot easier for myself and the other healers
So it is an encounter to encounter thing, but if you had to stick with one then probably Disc.
My guild (Whipe on Frostmane, currently 6/7 hc) uses the following healing setup:
Priest, Paladin, Shaman.
On some encounters in Firelands Heroic, it's recommended to use only 2 healers (Alysrazor, Rhyolith), and on 1 fight it's mandatory (Baleroc).
This is the reason for having shadow as dualspec, unless one of the other healers got a dualspec as dps already.
If you don't want to respecc alot, it's adviced to be disc for several reasons. You already got a strong hot-class (the druid). It's always nice to have additional raid cooldowns (PW:Barrier). Divine Aegis stacking can be of great help sometimes (Majordomo, Beth'tilac). Smite+Atonement can help with enrage timers or softenrages (Beth'tilac, Majordomo). There are 2 fights were I'd prefer to be holy, but I'm probably gonna stay Disc on those for now (Rhyolith, Ragnaros).
This is my opinion and it doesn't have to be right, it all comes down to which spec you are most comfortable with.
---------- Post added 2011-07-19 at 10:58 AM ----------
Ragnaros, Beth'tilac, Majordomo are the 3 hardest encounters in Firelands if you ask me (hence the big focus on those 3 bosses)
offer to pay for the respec from the guild bank coffers. it can easily afford to do so i assume if your 7/7. test the fights. if (s)he is normaly holy take somewhere neutral and easier like baradin hold and see how disipline works.
remember initialy it may be slightly worse as your healer is learning a new style and learning in placs like BH can be useful. as it's a reltively easy fight but stil requires raid aoe healing and tank healing.
Both specs will work fine, I would suggest playing what she is more comfortable with as it will be the better choice regardless of what fight you're on. If a certain fight really requires Disc she can always respec for that one fight, it only costs 60g or so, That's like half a repair bill.
With that said if she is 100% equally comfortable with both specs I think in a 10m Disc might be slightly more versatile.
This is a tier in which almost every boss strategy works around coordinated cooldown use. Disc has Barrier, one of the strongest raid cooldowns, holy has nothing.
Even if holy had a raid cooldown, your priest should still go disc, because disc heals and absorbs for more than holy heals.
Even if holy healed for as much as disc heals/absorbs and had a cooldown your priest should still go disc because absorbs have strong synergy effects with normal healing which are not shown on the meters.
Even if holy had some mythical advantage that made up for all of this and a raid cooldown and some extra benefit that made up for the way absorbs work with normal healing your priest should still go disc, because there is no spirit gear in firelands and disc can get away with a lot more spirit free items than holy. Disc will gear up faster in a raid that does not drop spirit cloth.