Holy vs Discipline
Holy and discipline are pretty much alike in their ability to handle heroic healing at the moment. Holy has better mana regen and aoe healing, disc has better point healing. But none of the specs handles any area badly. I'd say holy is slightly easier on lower gear levels, and disc picks up later on, but there is a buff coming up to disc that might change this. What you decide to go for should be based on which spec you feel most comfortable in.
If you feel like you'd want to know more about disc healing, Malevica wrote a good post on it. It's focused on raid healing, but heroics sure feel like small raids nowadays. She does point out that aoe-healing is a weakness in disc healing, and you'll notice this even more when you're all alone to handle it, like in a heroic. I've also written a post on How to heal as Discipline in heroics.
Evangelism and Archangel?
Without Atonement, Evangelism and Archangel aren't very useful. The net profit from casting smites to regain mana is very low, in fact I think it is nonexistant. If anything you'd want this for the increased healing done, but it comes at a high price. We wouldn't be able to take some nice talents in the shadow tree for one. Another problem is actually being able to throw those smites. In most heroics there won't be much time for this, in raids it is definitely non existant. I strongly recommend against going for these talents.
Serenity vs Sanctuary
Choosing Chakra stance will make alot of difference for your healing. Both because they buff different spells, and also because that will make you want to use slightly different skills. Throughout the various heroics I've done so far, I can however say that I choose Serenity 95 times out of a hundred. Even when there is tough aoe damage. Right now the main reason I choose Sanctuary in a heroic is when I want to place a Sanctuary. The conditions that need to be filled for me to want to do this are many, so this doesn't happen often at all. I'd have to know that nearly everyone will stand in one place, where I can use Sanctuary, and the aoe damage has to be pretty damn high. Another reason would be if I know I won't be able to throw a Heal. If I know for sure I will never be able to stand still to do the cast, Sanctuary will be better than Serenity. Fortunately (?) these extreme conditions are rarely met, and so I decide to stick with Serenity. This isn't always true in raids, but very often the case in heroics. There are several reasons why Serenity is a better choice for heroic healing;
- You get an instant cast in Holy Word: Serenity. It's cheap, it heals for pretty much (comparatively) and best of all, it's instant, like mentioned. I love this skill in heroics, because it really helps alot with the healing in the damage environment that I feel heroics have. You don't have the need to place a Sanctuary very often, but a Serenity heal is always useful. All you people who are pro SoL should really love this skill.
- If you have the possibility, there is great mana efficiency in refreshing Renew on the tank with the occasional Heal throughout a fight. I will talk more about rotations a bit further down, but right now this is my main way of healing. And refreshing means no extra mana cost, which makes your mana pool happy. When there is moderate aoe damage you can do the same thing to the whole party. Just throw a renew on affected targets and refresh if damage says they'll need more healing.
- Serenity increases the critical strike chance of your direct healing skills by 10%, which makes it alot easier to keep up Inspiration, which will further lower the damage of your tank and save you mana.
I did initally use Chakra Sanctuary alot more because I felt like the 15% extra aoe healing would make a big difference. I quickly learned however that you only want to resort to aoe healing when you really have to. Your mana won't allow for much more. As long as you can you want to keep things alive with hots and Heals. So let me get this clear - Chakra Sanctuary isn't bad because it's bad, but because it doesn't suit the healing needed in heroics very often. You only want to get into that wasteful way of healing when you have no other choice.
Like I've mentioned the beauty of Chakra Serenity is that it will make your direct healing skills refresh Renew, so it could be good to know exactly what a "direct healing skill" means. It's not as simple as you'd think.
Direct Healing Skills are;
- Greater Heal
- Flash Heal
These don't count although you might think they would;
- Circle of Healing
- Prayer of Mending
- Holy Word Serenity
- Prayer of Healing
- Binding Heal
- Lightwell Renew
Inner Fire vs Inner Will
The best thing to do would be to switch between these skills as needed. Unfortunately when things go rough that is an ideal that is difficult to live up to, so you usually have to decide for one of these when starting a fight, especially boss fights. Since I usually stick in Chakra Serenity, I often choose to keep Inner Fire up. If I am capable of refreshing my renews I won't need to recast them so often to benefit enough from the mana reduction from Inner Will. But this is during the "simple" fights, aka when I will be able to refresh Renew fairly often and don't have to use CoH, PoM and other instants. Although heroics are difficult right now there will be plenty of trashpulls where you'll only have to focus on the tank, or at least only have to focus very little on the rest of the group. For those pull Inner Fire is ideal.
But then there are the pulls and boss fights where you will actually have to do alot more. Inner Will is great in that it not only reduces the mana cost of the majority of your skills, it also provides run speed. Run speed is so awesome Blizzard completely removed it from Unholy Aura (party wide that is) because it was OP and even gave feral druids a skill that does nothing else (Stampeding Roar). So do not underestimate how valuable it is to be able to position yourself quickly. There will be plenty of fights in heroics where you'll be glad for those 10% extra run speed.
So to recap - Inner Fire as long as you can heal people mainly through Heal, and Inner Will when you have to start using other skills more.
As for any healer there isn't much of a rotation to talk about, but I'll mention the most mana efficient way of healing in different situations. Of course the fights don't always agree with you being mana efficient, and that is when you have to pull out the more expensive tools.
- Easy damage on tank and group - Inner Fire, Chakra Serenity. Keep Renew on tank, refresh with Heal. Heal is so cheap you can throw it even when it is a complete overheal. If a dps goes down low you can give him the same "treatment", aka throw up a renew on him and refresh it until he's fully healed.
- Medium damage on tank and group - Inner Will, Chakra Serenity. As above, but also throw in Holy Word: Serenity where needed. It's best used on the tank since it boosts your crit chance on the target further which will proc more Inspiration. For small aoe damage the occasional Circle of Healing works good, or even Prayer of Healing (I feel like the range on Circle of Healing is alot more than 15 yards btw).
- Difficult damage on tank - Inner Fire, Chakra Serenity. When the tank dips use Holy Word Serenity followed by two flash heals and a Greater Heal to top him off. This is emergency healing and shouldn't be used too often. If damage is hard on the tank for a longer period of time, consider placing a lightwell beside him to have him help you with his healing.
- Difficult damage on group - Inner Will, Chakra Sanctuary. Things rarely go this tough and when they do you often have some dps who can help you with some aoe healing for a short period of time (in any case you should tell them to be ready). If you know aoe damage will be tough, place a lightwell at a good spot so everyone can heal themselves in addition to your healing. Place a Sanctuary if people are huddled. Get PoM going every cooldown and spam Prayer of Healing (throw in some CoH too). This is the "easiest" healing since all you have to do basically is loose all restraints and hope you don't oom too fast (but you will). This is what resembles Wrath healing the most.
Skills, and when to use them
Cataclysm has put a big "ah ah ah" tag on all our heals, and we have to take them through custody before even thinking of using them. Here are a list of our heals with the general area of usage;
- Heal - Our basic heal, can be used as often and as much as you like. That sounds awesome, but that is only because it is insanely slow and small so even if you spam it around it won't make a big difference. Spamming is what you'll do with this spell. Use it to refresh Renew on your tank target mainly, and rest of the group if minor damage is going around.
- Greater Heal - Is nearly 3 times as effective as a Heal and costs 3 times as much. As such it is almost like casting three Heal at once, and should be used instead of Heal when damage requires it. Note that it is slightly less efficient than Heal, so it is always better to use Heal when possible. Also refreshes Renew.
- Flash Heal - Costs as much as Greater Heal, heals for little less and is twice as fast to cast (note that you can talent down Greater Heal to cast faster, but not as fast as Flash Heal). Should only be used when damage on the tank (or someone else) is too high to handle with Greater Heal or Heal. Could be combined with Greater Heal through Serendipity for better throughput.
- Prayer of Mending - Alot of healers are using it like they did in Wrath, aka always keep it up on the tank. PoM is only half as mana efficient as Heal, which means it has to jump at least twice to be worth to cast instead of Heal. Because of this it should only be used when you know it will do this. Most trash pulls won't require you to use PoM. It is pretty safe to use for most boss fights however.
- Circle of Healing - Costs little more than two Heals, and heals for about half as much, making it 1/4 as effective as Heal. This means you should try to use it only when 5 people can benefit from it, or when aoe damage is such that you need to complement Prayer of Healing.
- Prayer of Healing - Heals for about as much as a Heal and costs little less than 3 times as much. Can safely replace Heal when 3 or more targets benefit from it, note that it doesn't refresh Renew however!
- Binding Heal - Can basically be used as it was back in Wrath, with moderation of course. Even when hitting two targets this is slightly less mana effective than using Heal twice, but extremely more time efficient of course. You shouldn't hesitate to use it when needed. It stacks serendipity but doesn't refresh renew.
- Shield - This used to be one of the least mana effective spells for holy, but nowadays it is actually more mana effective than Flash Heal. Because of this it can safely be used in any situation where you'd feel inclined to use a Flash Heal. Just as with Flash Heal this kind of healing will oom you fast however. Mostly we save Shields for using Body & Soul.
- Lightwell - You can read about how to best use the Lightwell in the post I wrote about it!
- Divine Hymn - Extremely mana efficient and should always be used in a pinch.