Dungeons in any game dating way back to the SNES have never been difficult or challenging, little more than glorified loot piñatas to beat on. Expecting a dungeon to be difficult in this day and age is giggleworthy. On that note, 'fun' is a very subjective term. What you consider 'fun' someone else won't, and what someone else finds 'fun' you won't, so there's not much point in discussing it.