There's a subjective part to this; what's considered being fun by someone?
I, for one, like to take the time to actually read the NPC dialogues and the mission descriptions for quests as to me they have an entertainment value, but from my experience the majority of the players don't give a damn about all that "wall of text" being thrown at them during quests.
It was supposed to be fun to get to know more about the game world and the story, but most players are not interested in that.
One thing many people reason with regarding this is that "but I have done this quest once already, so it's boring to have to go through it again". Well, it may be, when you are powerlevelling your newest alt through them on a monthly basis. But playing the game at a more reasonable (or should I say, sane) pace would pretty much leave you with not running into the same quests again for months at the least, during which time you will have forgotten most of them anyway. Sure, it will still be somewhat repetitive, but more like catching the re-run of an liked TV show episode every now and then instead of having it played 24/7 in a loop.
Same thing goes for travelling/exploring the zones, Scheol and the quest lines there being a perfect example of this. I've not spent much time there, and thus didn't see much of the zone, until these quests were introduced, and they made me to realize that there are a lot of awesome places in Scheol. Get to see them (and later, when doing the quest with another char, revisit them) turned out to be much fun for me.
Then again, it isn't fun for most of the players either, as it just takes time away from being able to grind more XP in the most efficient way on the mindless rush to 220.
What would be fun for them then, at least as far as quests go?
What is indeed a common problem with most of these quest tho is that they are way too hard for the intened levels to complete them alone or in a small, non-optimal (read: without uber tank and doc) random team.
And requiring a 220 orgmate/friend/whoever to babysit you through quests takes away even that little feel of achievement and fun you'd be getting if you could, through some hardships and difficulties, but still, complete the task yourself instead of watching how a 220 ganks everything for you.