Up to what point have you played? Just curious.
In terms of dungeons the highest level I have played is Cutter's Cry. Admittedly the Chimera fight can a bit tricky but the rest of the dungeon is just walk through and blast everything. Maybe because I am a mage it's just so easy for me to position myself well and away from any danger. It may be too early to judge but I'm just saying my thoughts on what I have played so far.
The only dungeon I can say genuinely brought the pain was Sunken Temple of Qarn. That was legit. I would love more content like that.
I think part of it has to be because it would be twenty times harder for new players if they didn't nerf stuff. Roulette exists to basically bribe experienced players into rerunning old content to help increase the number of groups available for newer players. While a lot of experienced players are really nice and helpful and willing to explain, there's also a large chunk of the player base that is only there for the roulette bonus and wants to speedrun everything. Challenging mechanics that will wipe the group as newbies get acquainted will just cause the impatient people to abandon. Nerfing the dungeons makes them easier to get through and less likely to fall apart midway.
I got to listen to a healer and tank discuss the tank having bailed on a previous Pharos run because DPS was "too slow"--then later imply that anything under i90 was too low for an acceptably speedy Pharos run. Anyone that impatient won't want to redo Demon Wall until people get it down, so it gets nerfed.
Hmmm... I see...