From my skimming through all of the playable classes and their respective skill calculators, I believe that only the Monk would be able to be a dedicated healer for a group of players (please correct me if I'm wrong). I was attempting to come up with the most effective combination of healing and damage reduction for the group primarily and good spirit regen secondarily.
Crippling Wave - Obsidian (Concussion): I am wondering if Concussion stacks with the passive Resolve, or if Concussion will simply override Resolve since it is a more powerful damage reducer. I also assume that if they do stack, it will be for a total of 65% damage reduction and not 80%.
Sweeping Wind - Golden (Inner Storm): Should be easy enough to create and maintain a full stack for the 1.8 sps buff. Will be 2.16/2.1/2.2 sps including The Guardian's Path 20% spirit bonus passive, depending on internal rounding.
Breath of Heaven - Indigo (Circle of Life): Seems like a no-brainer for healing. Increased range would be nice, though.
Inner Sactuary - Golden (Safe Haven): I think overall the Safe Haven rune will result in more net HP than the Circle of Protection (obsidian) rune, though it depends on how much ranged damage is incoming.
Serenity - Golden (Tranquility): Group immunity for 3 seconds? Yes please!
Mantra of Healing - Situational: I chose this over Mantra of Evasion simply because I am assuming there is a Barbarian in the group and the other two members are ranged. I think that if the group is pure melee, Mantra of Evasion would be a better choice. As for the rune choice, I really think that depending on the situation, each rune is equally viable, except possibly the Indigo rune which might be trumped by the Obsidian rune in effective HP, depending on the vitality -> hp conversion. Defaulted to obsidian rune.
Resolve: Hopefully this will stack with Concussion. If not, I would probably go with Exalted Soul for more spirit playroom.
The Guardian's Path: Obvs you'll be using a 2H weapon.
Chant of Resonance: Less hassle maintaining your mantras. Plus 1.2 sps with Guardian's Path.