for me, and i assume many others, the core experience of an ARPG is improving your character. there are three ways to do that: clearspeed, boss DPS, and defense.
clear speed in LE is mostly finished by the time a character starts endgame. you have all your skills and they’re all level 18-20, and there’s little to no clear speed bonuses on gear (such as AOE increase, explode on kill, etc). i think that’s fine. LE isn’t a game about clearspeed, and it doesn’t need to become one.
some people enjoy building their defense, but personally i just try to get as much as necessary for the content i’m doing. i see it as a ‘necessary evil’.
that leaves one avenue for my character development: boss DPS. but every single character i have, regardless of if their single target DPS is extremely low or extremely high, takes the exact same amount of time to kill bosses after this adaptive DR was implemented.
i know that you have been and plan to continue tweaking this mechanic, and that your stated goal is that 80% more player power should result in 50% faster boss kills. i don’t think this mechanic will ever achieve that with the way that it works, and there’s way too much of a downside to it. it’s depressing trying to increase your character’s DPS and seeing no increase in kill speed. i understand the intentions behind this mechanic, but it’s throwing the baby out with the bathwater.
additionally, the mechanic can be cheesed by designing your character to do extreme burst in very short periods of time, circumventing the adaptive DR. meanwhile, characters who deal a steady stream of DPS experience the maximum possible ‘punishment’ of adaptive DR.
my suggestion: don’t be afraid to kill your darlings. you tried this mechanic, it hasn’t worked. remove it, and instead take a surgical approach where you find which sources of damage scaling give players excessive DPS and tone them down individually.