Yep, this is actually my point entirely with this. If a low-skilled player on X job can do everything a mid-skilled player can on a Y job, that means X job is much more powerful than it should be and there should be some balance between the two.
In the current iteration of healers, we don't see that divide. They all contribute similar things in different ways. There are some divides there, yes, but it isn't the massive gulf that is there when you compare WHM vs AST in the 3.4 era when AST had better MP longevity, better raid utility, and basically equal DPS.
Now that we're at the current state, people shouldn't consider swapping out healers to something that is deemed more optimal unless the group is striving actively to reach the absolute heights of speed killing.
[edit] Just edit this point a bit more for clarity's sake. In this discussion I'm not speaking towards job imbalance but more speaking towards an individual's contribution to their group. Even if the current meta is AST > SCH > WHM, a WHM who's comfortable on their job but not comfortable with either SCH or AST will most likely contribute more to their party than if they made the swap.
We're all not world first raiders or speed kill specialists. We all have different ranges of skill sets and abilities. Even if AST in theory outclasses SCH and WHM, it's still possible for the individual's skill and comfort with WHM to contribute more to their raid versus playing AST.
My definition of throughput is HPS spikes versus total healing potential. Diurnal AST has a higher healing potential cap versus WHM because their heals are overall stronger than WHM. However, AST's weakness in this regard is the fact that they're mostly constrained to their GCD in order to actually spike heal. Essential Dignity and Earthly Star from AST vs Tetragrammaton, Divine Benison, Benediction, Assize, and Plenary Indulgence from WHM. This means WHM itself has better tools to clean up oopsies if called for. Not to say AST can't do that, but WHM has more potential for wipe recovery versus AST because of their MP longevity and multitude of oGCDs at their beck and call.
This means very little for raid groups already clearing Shinryu and Omega (Savage) and have the content on farm but has significantly more bearing on those groups who are commencing with progression. In some respects this is why I disagree with using log data as a total healing potential metric because you also can't measure potential on farm groups because, well, they're doing their best to minimize necessary healing and how they go about achieving that is different from group to group, not really giving a solid picture of the healing.
If you use Neo-exdeath player healing metric, you can see there are far more WHMs versus ASTs but I still don't think that's a fair judge either as we don't know the context of each individual group on the list either.
One will definitely find more mileage out of the WHM kit in less structured environments such as Rabanastre where mechanical slips can and will happen but it's also not to say going with SCH or AST makes you a weaker healer either. It just means you need to approach if differently too.
I personally don't think I used the term "massively" ahead, but correct me if I'm wrong in this regard. I do appreciate AST has stronger GCD heals while WHM has more oGCD heals and players should use the individual kits accordingly to their strengths.
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On your topic of Assize versus Reiryu heads in Shinryu, I have seen you state that earlier this week so I decided to try it last night while we're doing Shinryu. Here's the Twitch clips for it. Unfortunately, Assize doesn't seem to heal Reiryu's ; ;
I do think the worst part of the heal check is trying to target the adds in the final phase when the massive honking hit box of the boss is in the way, lol. While I don't think the mechanic is the most interesting of heal check, I can appreciate the developers going out to try something new. I hope this leads to better and different heal checks in the future.
And yes, I also do enjoy deleting an add outright with Benediction. lol.