PRE/CON/REC will help with survivability a bit, but if you want a better chance at crit heals (which most like), PRE/DEX/REC. Mostly, depends how confident you are in avoiding damage/healing yourself in exchange for better heals. But in all cases, stack the absolute most you can into PRE.

Energy builder and shield are your flavor, pick which you like more visually. You can technically get away with not ranking your shield since you can already heal yourself through big damage, but R3 is better insurance.

Compassion is the only form to worry about as a healer/support. (Unless you wanna be a CCer, then Manipulator is another story)

Conviction is the best clicky bandaid for yourself. If you take the AoE advantage, it helps others around you also. You can also use Bountiful Chi Resurgence instead, it's a heal over time on yourself.

Iniquity is the best single target heal in the game (avoid the advantage). Celestial Conduit is also nice, but less convenient (but it looks way cooler)

Take any ressurection power, but make sure you take the advantage to pick up more people, rather than single target. All res powers have the advantage (minus the serum from gadgeteering)

Moonstruck is basically Pillar of Poz, which is a good power to have to keep people healthy in your immediate vicinity, only difference is visuals.

Bionic Shielding is the go to for set it and forget it, R3 it, and put it on people you can predict are about to take a hit.

The important bit, your passive. Aura of Primal Majesty/Arcane Clarity/Ebon Destruction/Radiant Protection, are the most used/well liked in order. You will have no energy issues with the first 2, the latter 2 may give you some problems with energy, but can be fixed with a few points in REC/END. The more PRE you have, the better your aura will be for everyone.

Mental Leech is a good tap and forget power for melee/tank healing. Don't have to rank it, it will passively heal anyone near it (1 target) as it slowly churns away, so always good to tap it off cooldown.

Vala's Light is my absolute favorite heal, but you'll find people dislike it for the the cooldown it has. If you take AoAC as your passive, the cooldown is super negligible, but it's still not much in my opinion in the first place. It acts as a heal bomb (a sphere around your target you cast it on), so you can lob them on groups and let the heal slowly work away on them (the advantage is important for this.) Arcane Vitality is the other AoE heal which is still amazing, and you'll find most like it more for some reason. But it's a conal heal, who will heal your target, and anyone in between you and them. Take either, after playing with them a bit to see what suits you better.

I admittedly just use Ascension for theme/flash, but it works wonders on giving you a good burst of enhanced healing potency, and a good break free from holds at cosmics, so I do recommend it.

Illumination/Sentinel Mastery

If you decide to keep the bubbles from PRE mastery, Illumination is good to tap on the target, as it'll cause anyone hitting the target to heal them for a small amount. The buff lasts 20 seconds, so don't worry about spamming it.

If you decide to use Sentinel Mastery, which actually is the best way to heal everyone via a stun/paralyze/incapacitates/sleeps, I recommend Taser Arrow, or search for any power with a short cooldown that applies one of those 4 effects, instead of Illuminate. The passive healing from this in a large group setting is rather monstrous, so I'd try it out. I just use PRE mastery cause I don't have the heart to change my original build :(

You have 2 ADV points left for your TP here at this point, depending how much you ranked your block. The last power can be Resurgence for the insane heal it will give you in emergencies, Indestructible for the solid damage reduction, or Transcendence, the celestial ultimate, which is probably the best option for that massive emergency button when things go bad. Or a self resurrection (the fire set one being the best)