Please forgive me, but I'm not going to reply to a lot of that. In the end, some of it is flat misinterpreting intentions ('adjustable' was referring to dev typically toning down on what the proposed dififculty is, barring ultimates)
I responded to that possible meaning in the very same sentence.
However, I will say that I heavily disagree that I underestimate retention and engagement.
The obvious inversion -- I said you
overestimate player retention consequent to the weekly grind loops -- aside, you've conveniently left out the parameters again, despite having quoted them right at the head of your post: "I think you... underestimate just how dull
the pull-to-gate-AoE-pull-to-gate-AoE-boss... hallway sprint simulator can be even to new players."
Drumming up excitement for a new feature, rather then continuing to drag down the old feature, which truly isn't likely to change all that much.
Such would perhaps be novel... if any attempt to offer new features wasn't met with "No, that'd conflict with the tried and true designs optimized for (hallway sprint simulator) roulettes," as you've done.
And let's be clear here; I haven't tried to "tear" or otherwise "bring down" expert roulettes as they stand. I've merely butted heads with the insistence that they are all that dungeons could ever be designed to be, or that there is no place in 4-man content for further designs, and have pointed out how the current roulette reward system unnecessarily constrains creativity in dungeon design by offering the same bonus at completion regardless of dungeon length.
My 'grand revolutionizing', as you seem to take it, has been only
to ask that Expert Roulette's rewards more more properly scale -- or, at worst, be less overwhelmingly more efficient than other means of weekly tome-farming, so as to be less obligatory among our weekly activities.
People were discussing issues of difficulty, but honestly, I'd like to see more along the lines of depth of mechanics.
Those discussions inevitably meet. The majority of times increased difficulty has been suggested across the various dungeon design threads since ARR, that difficulty has been suggested in the form of deeper, more impactful, and/or more integral mechanics.
The problem is that those discussions have inevitably been tugged astray or bludgeoned with the reductive hammers of "but players can't handle that" or "it wouldn't be tome/minute efficient enough to compete", to the point that any concrete discussion gets bottlenecked by the larger warrants of whether the game can even allow "dungeon" and "depth" to exist in the same sentence without negation. That's why you see so much jaded discussion. That's why you see so many broad strokes. That's why you see discussion of the surrounding systems, so that a context for more than the most basic, uninspired, copy-pasta dungeon designs would be actually viable.
But, by all means, have at it. Mechanics are certainly more interesting to discuss than fighting the same policy-centric fights.