I'd like to say that the context of my comment was to compare the mitigation kits of Nocturnal AST and SCH since it was brought up as part of the discussion. While its true that healing in general is a very dynamic role in the party mechanic, it's still important to consider what tools each kits brings to the table on an individual and static level so one can gauge their uses and effectiveness. While the divide between the mitigation kits of Nocturnal AST and SCH might not be as great as some people consider, it still favours SCH in terms of raw mitigation.
You absolutely have to consider the critical bonus of Adlo because its a defining feature of the spell and the only healing spell to date that has that kind of bonus on Crit. When Adlo crits, its effectively one of the most potent and cost efficient mitigation tools in the game.
With that being said, Adlo is better than N.A.Benefic in terms of raw overall power. What N.A.Benefic has an advantage over Adlo is the fact is consistent and overall lower potency / MP cost. Both have their niches.
Note that I never said "Adlo is better" in my quote. I only mentioned that the average shield strength starts to exceed Aspected Benefic's shield component giving it an edge in the mitigation department over the course of a long fight. Aspected Benefic has its own uses as I've mentioned above.
I didn't state anything about why I used that comparison but it's an apt comparison when you consider the context of raid busters that hit the table. I didn't include Collective Unconsciousness or Sacred Soil in this comparison because chances are both casters would be using these ability in conjunction with their mitigation tools to reduce the overall raid buster damage and since both reduce the same amount of damage, they effectively cancel each other when comparing the two.
Take Sephirot's raid buster after P2 for example. AST would pop Aspected Helios with Collective Unconciousness. SCH would pop Sacred Soil with Deployed Adlo. There's a clear winner in that scenario. And you'll see similar results for any raid buster with that kind of wind up.
It's true that Aspected Helios is more readily available and it does overcome Succor by 5% as it should. Again, this lends itself to the fact Noct AST provides more reliability and consistency with their mitigation tools while SCH has more raw power behind it on the things that actually matter.
As a tangent, the more I try to use Nocturnal Aspected Helios, the less I like it. With SCH, their only choice for a direct AoE heal is Succor when Indomitability is on cooldown. This is versus AST who has access to both Helios and Aspected Helios. Both provide the same potency in healing but Helios costs less MP and heals raw HP which is arguably better than eHP. If you know for a fact that your raid can survive the upcoming raid buster it's better to just heal the wounds with Helios after the fact. Alternatively if you need to top people off prior to a raid buster, it's better to use Helios to get people topped off unless they're at a very niche HP requirement that is between the healing amounts of Helios and Aspected Helios. I can't think of a good adjustment for N.A.Helios right now but it would be nice it felt more... usable in the N.AST kit. Ah well.
I would like to see the testing behind stat reduction and the damage it mitigates. If you consider my testing here, I show that Disable and (Super)virus reduce damage on a similar curve. The test itself can certainly be flawed as I did it by testing Gravity on two targets where it does "10% less (damage) for the second (target)" to simulate what effect Disable might have on Gravity which may not accurately simulate what effect Disable will have on a monster. Likewise a player losing 15% of their stats results in a 15% drop in damage but the damage formula may be different on monster than it is on players. I will change my thoughts behind this if you can provide some information that runs contrary to my own results.
Likewise, I would be curious to see what Darkness damage is. I understand that it's a damage type that can only be reduced by things that directly reduce damage like Disable, Sacred Soil, and Collective Unconsciousness and would like to understand this damage type more. So if you have any information in the matter, I'd like to see it. Unfortunately, a Google search for "Darkness damage FFXIV" leads to a ridiculous (and perfectly expected) amount of random DRK pages, lol.
With that being said, the reason I'm using a Succor + Sacred Soil + Supervirus vs Aspected Helios + Collective Unconciousness + Disable comparison here is to just show that even without Deployed Adlo, SCH's tools are superior to AST's tools because the 15% mitigation Supervirus provides is 5% higher than the 10% disable provides. Even with the 5% healing boost to Aspected Helios it would be hard press for AST to match SCH.
But as I mentioned above, healing is a very dynamic role. When you look at Disable vs (Super)virus, Supervirus will generally win hands down due to having both higher damage reduction and longer duration. However, Disable is advantageous against the aforementioned Darkness damage and also advantageous in other scenarios too such as Cascades in A3S where Disable is available on every single Cascade versus Virus being available for every other.
The one concession I will add is that it's possible for the AST to overcome the mitigation gap by having an Expanded Bole primed and ready. If we're going to go with the discussion that Adlo provides more raw power due to crit, then it's only fair to have Expanded Bole available as well because RNG is well, RNG.
Again, I'll just point back to what I said at the beginning of this wall of text. Contextually, my comment was speaking directly to the mitigation kits and only the mitigation kits. I feel it's important to consider the individual tools each kit brings to the table and see how they compared to each other to determine the strengths and weaknesses of each job as this also helps players evaluate the overall toolkit each job brings as well. Not only is this comparison useful for overall strengths and power level, it can also open up ways to determine how toolkits may be more suitable for certain fights. For example, the Sephi EX fight seems tailored for the AST kit. T1, T4, and T5 was very favourable for a double SCH setup. Heck, I'd even argue T13 being great for double SCH w/ Eos as well since you're basically having Rouse'd Fey Illuminate Whispering Dawn + Fey Covenant on every single major AoE with each SCH being able to shield / heal their respective tank through Akh Morn.
I will admit that I am amused that you did make a comment about how most posters don't consider the full berth of the entire tool kit each job brings to the table and the critical importance of this. I do agree that it's important to consider all factors of a kit but find the irony that this comment stemmed from a chain of posts that started with one of my posts when I had provided a write up of what I felt were the pros and cons of each healing job just one page earlier.
With that being said, I'm always willing to learn and if more information crops up that runs contrary to my train of thoughts, I'll gladly accept that and change my thought process to suit.