Key things to remember about mana regeneration and management:
- No chain potting
- No downranking
- Access to Hymn of Hope – I advise stacking Priests together in raids. This way they can all maximize their Hymn. Set up a Priest rotation. Work with other Priests and time your Hymns so that no more than 1 Priest is out of action (1 Hymn per minute maybe?). It's a channeling spell so park yourself in a safe spot. Last time I checked it was party only.
- Replenishment – It's a mana regen buff that restores 0.25% of a player's maximum mana every second. Make sure you include a Retribution Paladin, Survival Hunter, or a Shadow Priest. 10 man groups will benefit from having 1 Replenishment buff while 25 man groups could use 2 of them.
We can't cast Greater Heal as much before (since we can't down rank). In terms of direct heals, we're stuck with Flash Heal and Greater Heal. Healers especially will need to pay a lot closer attention to to the health of their targets and what spells to use. Gone are the days where we could mindlessly cast Rank 3 Greater Heal and not have it impact our mana. For the Priests that go down Holy, I do suspect we'll see a higher usage of Flash Heal (due to Surge of Light). Any Clearcasting procs will utilize a Greater Heal (just because of that that is is a free spell).
With respect to buffs, if you don't already, please remember to keep Inner Fire up on yourself at all times. It may seem inconsequential, but the Spellpower increase does help. Picking up the Improved Inner Fire talent helps increase the potency.
Holy Nova is now a base skill. You no longer have to talent for it.
Lightwell has been vastly improved. Among the major changes is the fact that it no longer breaks upon damage (unless the hit taken is larger than 30%). The charges contained have been doubled from 5 to 10 and the cast time has been reduced to 0.5 seconds from 1.5 seconds. Restores around 4000 health over 6 seconds whenever a party or raid member clicks on it. Yes, this does involve the use of your group to understand how it works. Consider spending some time with them on the features that Lightwell provides.
Bonus: Come up with boss fights in dungeons or raids from Classic, Burning Crusade, or even Wrath of the Lich King where this spell would come in handy.
Guardian Spirit – I did a Skill Mastery post on this a few weeks ago. Do check it out for the long version! The short version is that this is going to be the panic spell of choice for Priests.
Penance – Eliah did a great Skill Mastery post on this a little over a month ago and his words remain sound.
Divine Hymn – This is another AoE healing type spell with a twist. It's a 1.5 second cast which heals a HoT heal for players near you and incapacitates enemies within 15 yards for about 20 seconds. This spell definitely appears to be made for PvP players.
Gems and gear
There's a certain number of talents that place a lot of emphasis on crit. Currently, the healing gear that we're sporting doesn't have a lot of crit rating (if any). I'm going to suggest holding off on regemming gear for the time being but start acquiring them anyway. Assuming you're raiding, I don't think you're going to need a whole lot of it. Stick to the Spirit and healing gems for now until Wrath is here. Since you'll be leveling from 70-80 at that point, the mana regeneration is longer an issue and you can re-socket for Spell Crit and Spellpower.
You're going to be replacing your current gear as you level up anyways. Yes, it hurts. I feel the pain. T6 epics will start phasing out in favour of quest or instance blues around the level 76-77 mark.
Current Flavor of Gems
Red: Teardrop Crimson Spinel or Teardrop Living Ruby
Blue: Sparkling Empyrean Sapphire or Sparkling Star of Elune
Yellow: Luminous Pyrestone or Luminous Noble Topaz
Potential Future Flavor of Gems
Yellow: Potent Pyrestone or Gleaming Lionseye
There's two arguments to be had here for replacing Spellpower and Int gems with Spellpower and crit (and straight crit) gems.
The argument for Int gems is that Priests can get more of their mana back from specific talents (Hymn of Hope and Rapture). Note that both of the talents state that a percentage of the player's overall mana is returned.
The argument for the critical strike related gems is that they'll offer a higher chance of proccing your various talents that take crit into account (Holy Concentration, Divine Aegis).
I'll leave that to the commenter's and theorycrafters to break either arguments.
At level 70, only two Major Glyphs can be inscribed. The third one opens up when you reach 80.
Raiding healing Priests may wish to opt for the Glyphs in bold.Note that some glyphs are not available until you head past level 70 (since Inscriptioners need to train in Northrend).
Anyways, use your discretion when it comes to Glyphs. Pick your Glyphs in a fashion that help augment your play style. Personally I'll be grabbing Power Word: Shield and Flash Heal to see how that holds up. If it's full of fail, I can switch easily (albeit expensively) to other Glyphs. The reason I'm picking those is that I believe it will help me out a lot when I go for the full Discipline build. Figured I'd let the other Priests have fun with the Holy tree for a while.
Don't forget to check out other stuff we have on 3.0.2