It would be nice if you added a deep, dark dungeons with bosses NOT INTENDED to be defeatable by normal means.
Im talking bosses that are hard even with magic resist cap/ Armor cap that would ruin even the hardest powergamers/Min maxers day

Like:
A lost ancient dragon priest of incomprehensible power.
A cave with a dracolich from ancient times.
An ancient vampire lord that has slept for milennia.
Unique ultrahard OPTIONAL bosses for people that theorycraft their eyes out would sure stop alot of "game to easy" threads and add very pleasurable scenarios for us who wants to feel scared despite being "uber".
The question isnt "Why would they spend time making this?" the question is why not? It would take MINIMAL effort from a dev point of view to add this feature.