I'll be covering the Mind's passive in more detail, taking a brief look again at the Grimoire's passive as well as covering the other two options, Seraphim and Medical Nanites. While we don't have a Celestial archetype just yet, it is only a matter of time before Cryptic adds one, so this will give a bit of a preview for what a Celestial healer plays like.
A quick recap on Primal healing
I covered Aura of Primal Majesty already, so we don't need to spend a whole lot of time detailing a pretty complicated passive. Just check out the link above if you'd like to know more, especially about AoPM's offensive benefits.
AoPM only does one thing: It raises stats. Your stats are boosted by a phenomenal amount, adding about a sixth of your superstat total to all of your stats (including your superstats). It also gives a scaling bonus based on your PRE to all of your teammates.
Raising stats does a lot of offensive things; it boosts crits and improves the energy management of your whole team. AoPM can grant a pretty sizable boost to crit rate and severity, turning infrequent, weak crits into regular, reasonably deadly crits. For allies specializing in criticals, it does not do very much, due to diminishing returns. It is a pretty big benefit to allies who do not, however. It also allows your heals to crit for bonus healing, although the crit rate is not really high enough to be reliable unless you spec for DEX. Grimoires who are super PRE/INT can run a fair amount of secondary DEX to improve their own critical healing power, which is worthy of note.
AoPM raises team survivability by raising ally PRE as well, which boosts the effects of their self heals. This is particularly notable for allies who have minimal PRE. It also boosts the healing power of Support Drones (either yours or a teammate's), which cannot be buffed in any other way.
AoPM's main boosts to survivability come from raising CON (increasing ally HP) and raising your PRE, boosting your healing power through the roof. While AoPM is considered to be a more offensively minded passive, it is quite functional for healers. It adds around 20-30% bonus healing, which is not as much as Seraphim but is still very useful.
AoPM also boosts the stats of your allies, thus buffing the power of any passive defenses. This is most valuable for teammates who are sidekicked or who have poor gear. Allies with appropriate gear should not benefit very much from this.
Finally, AoPM increases the power of click bubbles. No other passive really benefits them, so this is a considerable advantage if you are a freeform character who specializes in using Protection Field or Mindful Reinforcement.
The Mind's passive, Aura of Radiant Protection, also performs only one function. Instead of providing boosts to healing, it raises defense. It makes the character wielding the passive into a minor tank, granting around 50-70% more defense. As I mentioned last week, it almost turns the Mind into a tank.
Allies also benefit from the aura, although the exact benefit is dependent on your PRE. Generally, allies will take 10-20% less damage from attacks, although the exact benefits will depend both on your PRE and their levels of defense. High defense characters like the Behemoth benefit very little from the extra defense (thanks to diminishing returns), while most DPS characters will benefit greatly. Characters with non-defense defenses, such as Regeneration or Lightning Reflexes, also get a lot out of AoRP.
AoRP is considered to be the perennial team support aura because it does very little else. AoRP does not improve crits or energy management, nor does it improve your personal damage. It only provides defense, but the protection it provides is second to none.
The reason why adding defense is so valuable is because it multiplies the effects of ally self-healing powers as well as your own. If allies are taking less damage, healing becomes much more efficient. Because targeted heals are very strong in general, it also provides a more intangible benefit: It increases the amount of time you can react to a dying ally. Allies who live 10-20% longer are much less likely to die because having that extra reaction time makes you much more likely to deliver that life-saving heal. It also gives them extra reaction time on their own life-saving panic buttons such as Resurgence or Masterful Dodge.
Seraphim is an oddly named passive, since it is less suited to avenging angels and more suited to angels of mercy. Either way, it has two functions, rather than one. Seraphim boosts the power of your heals by a ridiculous amount, but it also improves all of your paranormal damage output by a significant amount. The boost in paranormal damage is less than that of an offensive passive, but it is still enough to make Shadowform mostly obsolete.
Seraphim's heal increase is roughly 50-60%, but it is multiplicative on the heal bonus from PRE. This means that Seraphim healers don't just heal more than other healers -- they heal a bleeping lot more. R3 Celestial Conduit goes from healing 600-700 to around 1000 per tick. That's roughly 2000 healing per second through taps, without counting any chaining from Illuminate. Celestial healers have a reputation as superhealers for a reason.
However, that level of healing isn't generally needed. Amusingly, Seraphim is better for boosting the heal power of weaker AoE heals like Arcane Vitality than it is for boosting the really powerful ST heals. It's also nice for increasing the power of Empathic Healing even before it has ramped up, since Empathic Healing heals more late in its maintain and is weaker early on. Overall, AoRP does a better job at helping the team survive because the main limitation for a healer is not heal power but reaction speed. Boosting the power of AoE heals to make them more effective is quite useful, but I suspect a Celestial archetype will not take advantage of this.
Seraphim also boosts your paranormal damage, which is fantastic for powers like Shadow Embrace, Ebon Rift and Ego Storm. It can also be an interesting choice for Telekinesis powers, although they are somewhat reliant on non-PRE stats. Seraphim heroes make excellent soloers because they melt through enemies quickly and can heal themselves well. My biggest problem leveling a Seraphim character was entirely reaction time; I often died before I could react to a bad situation.
One problem that Seraphim has is that it provides a periodic heal every few seconds to everyone within a short range of you. This heal is worthless, heals almost nothing, and generates aggro. This is kind of a problem, so Seraphim healers would be wise to open most fights on the defensive or positioned well away from enemies.
The good and the bad, but now the ugly
Medical Nanites is the worst passive in the game. Now, it's true that out of any pool of passive abilities, one would have to be the worst. However, Medical Nanites' level of bad blows every other passive out of the water. If given the choice between having no passive or having Medical Nanites, you're better off having no passive.
Medical Nanites heals all allies within a decent radius for a small amount every few seconds. This amount is significant; it's roughly a third of base Regeneration on your whole team. This healing isn't honestly very much, but it does have an effect and it is pretty nice while soloing or with a friend duoing missions. It's especially nice for soloing on the Inventor, who has Energy Shield and can block a lot of damage while his pets mop up.
When the going gets rough, however, Medical Nanites doesn't provide much support. The healing isn't enough to stop an ally from dying, so if you're a healer you will still need to react and heal. Unfortunately, because heals are so powerful in CO this really won't save you much. For the Inventor, it may be enough when combined with Support Drones if your ally starts blocking.
When in a team, Medical Nanites is a detriment. The periodic heal is next to worthless, and it causes a very big problem: threat. It heals each of your allies for a few hundred HP every three seconds (at level 40), which makes you a juicy target for mobs. Mobs will disengage from whoever they're fighting and dogpile you, pounding your face into mush. It is not a happy situation. In team fights, a character with Medical Nanites is better off blocking and doing nothing while his team saves his life constantly. This lets him function as a sort of ghetto tank with a tiny fraction of the survivability of a real tank.
This shouldn't discourage you from playing the Inventor, but do keep in mind that his passive is worthless.
All together now
- AoPM, the Grimoire's passive, benefits the team in many ways, offensively and defensively. It's great for any situation, although it is not the best while solo unless you build for Enrage rather than team support.
- AoRP, the Mind's passive, is the best for team survival. It lets your allies soak more damage and boosts your ability to keep them all alive. It's not as good as AoPM if your allies have a lot of defense.
- Seraphim, which is currently freeform-only, is the best for delivering raw heals. It also turns you into a significant offensive threat.
- Medical Nanites, the Inventor's passive, is more of a handicap on a good archetype than it is an actual useful tool. It is decent in general play, but terrible in big teams.