As I stated, this is "a starter thing" I did for the healer I was most familiar with (as in: both as it is now and as it has been in all the previous expansions). In time, I hope a similar thread can be opened to address all the other healers. But hey, writing this stuff takes time and effort, so let's just tackle each healer individually.
I know — and said — the Sprint from Expedient is never gonna be a necessity, but think about this: if you had to choose, would you sacrifice a 20s, 10% mitigation on a 120s CD for Sprint, or a weak heal on a 60s CD? The answer is obvious, as it is much easier to cover for the "waste" of a 320 pet potency heal than a long-duration, 10%, snapshot mitigation. Holos has a weak heal attached to its shields and mitigation — ideally you want to use all 3 effects, but it's not uncommon to just use it for the shields and mitigation, as the heal is never going to be as important, whether it is for prog or for optimal play. Consequently, a Fey Blessing that gives Sprint is objectively better than the way Expedient is now: it's less sacrificial, it's more flexible, it's more visually coherent.
Furthermore, the "depends on how good the team is" argument is flawed, as the reason you'd be using the Sprint effect is still in response to a specific type of mechanic that requires movement, wether or not you are playing with good or bad people. Improvising with the Sprint of Expedient was never a thing in the first place: it's a skill that requires planning.
Finally no, Expedient shouldn't exist on other Jobs. Come on: we complain about homogenization all the time, and we want a copy-paste of abilities spread across multiple Jobs? And to put a restriction such as the one you proposed to Expedient would feel very bad for three reasons:
1) You'd have to restrict fight design to accomodate such a tool;
2) It would create a "Liturgy of the Bell" effect, where it's effect is so specific 99% of the time you just KNOW you have to use it for THAT individual mechanic so you basically lose agency of when you want to use it;
3) I would consider it an unrealistic thing that is also very artificial;
Lastly, we are not seriously using caster up-time as a real argument for Expedience, are we?
See, you may think you've listed a number of situations in which Protraction is useful. But in reality:
1) In most situation Protraction won't save the life of a DPS because it's either unnecessary or too weak;
2) No tank needs the 10% extra HP to survive anything;
3) If you need to heal something, the heal-up bonus it's not going to make a significant difference, be it a person who's just revived or a Tank that's taking damage;
Ultimately, its use is to boost Recitation + Adlo + Deploy and even then it doesn't make or break anything and it's worse than Krasis.
I'm not sure if you've ever healed Savage content, but having done that as Scholar for quite some time, I can assure you the Skill might as well not exist. Which is not to say it would be useful in other contexts, as even in dungeon it is absolutely forgettable.
About the DoTs, it seems like you haven't pondered the meaning of your argument. The way you put it, you might as well remove healer DPS completely. Indeed, it doesn't matter if you have 1 button or 10: if you're not using your DPS options, "you suck" to cite your own words. But at least, an extra DoT with a different timer + the need to use Miasma II for weaving would make Broil spam much less obnoxious. Of course, this works for Scholar as it fits the Job thematically. Other healers need different solutions and I would not simply slap DoTs back on every healer — we can do better than that.
I've already answered the Expedient situation above. I can only add that changing Fey Blessing to a 120s CD Ability would not make a significant difference, but since it's utility is less important than that provided by Holos, I felt a reduced cool down was perfectly acceptable.
If I'm not mistaken, Aetherflow restored 20% MP in both ARR and HW and was reduced to 10% only in SB and ShB when Scholar (and Astro) gained Lucid Dreaming (ex-Shroud of Saints from WHM) as a Role action. In all these iterations, Energy Drain gave back 5% MP and Scholar was perfectly fine. So why would it be a problem now? Answer: it wouldn't — if anything, with Quickened Aetherflow back, Scholar's MP economy would just improve.
Like... I know full well the history of the Job since its inception. I'd say I've spent too much time studying it. So as that one lion guy said, do not quote the old magic to me xD I assure I've taken it into consideration.
In short — and I swear I don't want to sound abrasive when I say that — it feels as though neither of you know the history of the Scholar Job before EW or ShB — that is to say: before healer design went down the gutter — and neither of you have interacted with its kit in a meaningful way.