I like this idea. I'm not 100% crazy about some of your skill proposals, but I would love to see a healer class with so much flavor as this one. Man, I'm gonna go HAM with ideas over here.

For a change, I think the class's OGCD heals could be super powerful, but have a lot of risk attached to them, like losing your own HP for big heals in a relatively short Cooldown. Like, for example, with Sacrifical Nostrum you could top someone up to full HP, but take 75% of the damage healed yourself, reducing you to a bare minimum of 1 HP if the damage was higher than your max HP. This could be on a 1 or 2 minute Cooldown (compare to Benediction's 5 minutes) to make up for the fact that it can be very dangerous if not used with proper planning.

I kinda like the idea of healing others by damaging enemies, but I think it could work differently from what you currently have. Nightmare Scythe, for example, could sit on a 15 second CD: when you use it on an enemy, you get a buff called Marrow Drain or something like that, which lasts for the remainder of the skill's CD. You can no longer use Nightmare Scythe on enemies, but it procs into being usable on a party member to heal them for the same amount, or an amount dependent on the damage dealt. Once it is used on a party member, the buff disappears and you have to wait for the original duration of the Cooldown before using it again. If the buff falls off by itself, the skill as a damage ability goes back to being usable on enemies and the healing is lost. The potency for this spell could be similar to Lustrate or Cure II, as it would allow a similar number of big instant heals one charge of Aetherflow allows, while not being available on-demand like Cure and Benefic II are.

I would give the same treatment to Spiral Hell, but putting it on a 30 second cooldown, thus making it NCR's go-to source of on-demand AoE healing.

I kinda like the idea of converting Status Effects into MP, thus giving Necromancer an original way of MP management. The offset would be, of course, that no Status cleansing would yield no MP recovery, so in the end it wouldn't be amazing for raid tier content, since most things can't be dispelled anyways. Maybe paired up with Warrior it would be good? lol.

Lifesteal is great. Love it. I think Lifesteal itself could work as a permanent buff you put on a target, kinda like a "stance," which gets cancelled when you use it again on the same target or pick a different party member. This way, instead of refreshing your Regens on the target, you have to make sure to ALWAYS have your DoTs on the boss, or at least one enemy. If multiple enemies are afflicted by your DoT, it could increase the potency of the healing by 10% per mob, up to a set maximum of maybe 200% potency to avoid going real crazy. An addition of Choke II, and maybe even Choke III would, perhaps, make the regeneration effect stronger, forcing the NCR to prioritize DoT uptime on at least one target in order to get considerable regen returns. I'm thinking this single target regen-like healing should NEVER be nearly as strong as a regular healer Regen, since it is basically allowing them to heal a target with no cost at all while also DPSing. On the downside, it wouldn't work at all if a target was intangible, which would definitely nerf NCR's healing potential through invulnerability phases, forcing them to rely on direct healing instead.

I have another idea for party AoE healing, which would pretty much transfer the effect of Lifesteal to the entire party so long as they're within 15 yalms of you and/or the target of Lifesteal, increasing the healing potency by 25%. This could be on a 1 minute Cooldown, and would also benefit from more than one enemy being afflicted by the DoTs.

By this measure, NCR's answer to Divine Seal would be something akin to Raging Strikes, forcing them to choose between using their big damage cooldown in order to deal lots of damage, or save it for when power healing is going to be necessary.

I think that your Death Resurgence should work more like DRK's Living Dead works, basically making the target immune to dying for a little while, and then dropping dead after 10 seconds if certain conditions aren't met. I won't say "they must be healed to full HP," because we already have Dark Knight's version of that, but how about sacrificing the pet in order to bring them back from the dead? Putting a 30 second cooldown on resummoning the minion like Scholar's Dissipation does. The invincibility effect would be ignored by party-wipe mechanics, of course, and anything that goes through Living Dead. This would have to be on a 5 minute cooldown AT LEAST, however.

I would love -and I mean LOVE- if CJN wasn't a cross class for this, though. They could make up for losing Protect by having a similar effect of their own, something called Void Blessing that increases DEF and/or MDEF, and doesn't stack with Protect. Perhaps something a bit more creative than that. Instead, just have ACN and THM as the Cross Class, so that they don't miss out on Swiftcast, and, here's the best part: give them a Trait that transforms all MND into INT, which would allow them to wear healer gear without repercussions. Here's why: they wouldn't have Cleric Stance. How would they DPS AND heal, you ask? Well, their basic heal spell would not directly heal an ally, but instead damage a Necromancer's minion and tranfer the HP to them. The minion, however, would have a permanent Drain effect on its auto-attacks, so that it could have a steady source of HP refreshing, allowing NCR to have both MP and the minion's HP as their source of resource management. That said, in order to make up for the loss of the risk-reward playstyle that Cleric Stance imposes on all other healers, NCR could have a much more difficult DPS rotation that isn't just "put up DoTs and spam mini-nuke." Meaning that DPSing as NCR would be far more difficult than other healers in terms of skill, and thus, needing to interrupt your DPS rotation in order to do basic or emergency heals would be a big offset to your damage.

Another way to insert some continuous AoE healing on NCR would be giving them a skill that would eject a big chunk of the minion's energy onto the party, thus giving them a big AoE heal nuke on-demand (as Medica, Succor and Helios), but which would drain the minion's HP very quickly.

This means that maintaining the pet alive would be SUPER important, and to really drive this home, there should be a mechanic that does not allow you to resummon your minion for at least 20 seconds after it dies. This would make it so Death Resurgence's penalty isn't exclusive, and falls in line with giving a healer an on-demand immunity that would be usable on everyone: they would be sacrifing their basic healing spells and rely solely on their damage dealing to heal other party members, all of this timed by tight CDS on every ability.

I'm not crazy about Blood Pact, though I think it would be an interesting mitigation concept: making a Tank buster become a party wide AoE in order to help the tank with mitigation. It could potentially be game breaking, though, as that would give NCR the best mitigation ability by a mile. Then again, when you consider the ridiculous effects of a deployed critical Adloquium, maybe it's not that crazy. It would definitely have to be on a long cooldown, though. 120 seconds at the very least.

I think I've written enough. Your idea really got me going