Part of that is also because of the reward structure. The puzzles in Qarn, for example, were interesting to some because their loot could be used to craft different gear. There is an optional treasure chest in Haukke Manor that drops an item one can use to craft housing items. Most people jumping into roulette were not after those specific items, so of course they were skipped. Does not mean those bits did not have a reason to exist, do you know what I mean?
Imagine a dungeon that offers an optional path with an extra boss. Takes 5 extra minutes, but the boss itself gives extra weekly tomes, and an item thats part of a glamour set. Suddenly, there is an incentive to run the extra route.
Other mechanics exist that did not alter the dungeon structure, but rewarded the player differently. Saint Mociannes Hard had this interesting bit where you could wash mobs to make them weaker. One party member just had to open a valve, and the tank had to pull the enemies through them. These are small thing that make dungeons more interesting than the current "wallpull wallpull boss" structure. Those ideas have kinda been incorporated into Variant Dungeons, and I really hope Variant Dungeons influence regular dungeons a bit more going forward.