The Problem with Healer Feedback, and requested changes

[Shurrikhan]

I'm not even sure if they were EXACTLY supposed to be for that fight so much as their kit just worked for it, so it was a lucky coincidence.

Hard to tell back then. Which was maybe even a little charming in its own right.

But there was a point before Warlords, I think, where for a patch there was a glyph for Demonology where they could basically use their transformation as a tanking stance and legitimately tank 5 man dungeons, and some people played around with them doing harder stuff.

There was. Granted, one could also tank 5-man dungeons as a Beastmastery Hunter even go 5-DPS some 3 or more among Ret/Feral/Arms/Enhance/Frost (DK) back in the day, so long as the team was skilled enough. I suppose things managed to be more free back then even without necessarily increasing lenience, just due to there being less passive eHP bloat or such absurd active eHP peaks on tanks for that content to necessarily be tuned around.

Arguably within each there is a further subdivision with each having a selfish Job (SAM, MCH even now, BLM), and then ranges of utility.

Kinda, but that's only relevant to single-target buffs. Without a DNC or AST, there's really no difference between having a pure exploiter (SAM, MCH, BLM) or just taking yet another buffer.

Ranged (even MCH) are pretty clearly designed for a shoehorned Support Role in a game that refuses to have a Support Role.

Agreed, and it's a mess. I feel like that mostly comes down to their failure to ever actually make meaningful management out of MP (or even get close to that outside of maybe a couple fights within very particular eras) or, even more obviously, TP, instead leaving it solely as an unlikeable starvation for TP and MP users just to give BRD/MCH something to weave into their periods of low throughput. MP/TP were a decent Phys. Ranged mechanic, but they've never been a game mechanic, only a poorly implemented constraint.

It's not flawless, but it's far more noticeable and impactful than "Pure/Barrier" (which has been an utter failure to the point SCH/SGE is downright common) or "Main Tank/Off Tank" from ShB, which worked so poorly they dropped it. The only "real" Healer sub-role right now is "buffs the party" or "isn't meta outside of niche cases", with WHM getting the shortest end of that stick.

On a broader point, I feel like the game simply needs to decide whether they want (A), effectively, a few shades each of 4 jobs, or if they want (B) as many jobs as appear separately in their list.

If the latter, they may have to facilitate multileveling and simply accept that, depending on one's state of progression and what all others can bring to the table, some jobs may be advantaged over others within a given fight and that may be okay as long as, across the whole of time spent in these various fights, there's still a decent parity in value.

At that point, btw, something like your thought-experiment Support/Pure Healer distinction wouldn't be so bad. (I'd just still prefer to stay away from any such sub-role templating for the same reason I'd prefer to stay away from virtually any and all templating, and would have preferred, even, that we had kept WAR and PLD distinct and simply instead worked out the obvious balance oversights that plagued Warrior at the time.)