You can't be serious.
The Sacred Ashes quest starts with you looking into the mysterious disappearance of Brother Genitivi. There's this really unnerving aura around the entire quest as you learn more about him. The innkeeper at Lake Calenhad is jumpy, and then you get ambushed by cultists. When you go to Genitivi's house, you meet Weylon, who is acting really suspicious. You eventually discover the body of the real Weylon in a back room. Creepy.
Then you go to Haven. Really, this entire part of the quest is really well done. There's very little combat, but you're definitely on edge the entire time. All of the townspeople say creepy things and then you start finding body parts and blood altars, and then everyone attacks you. Eventually you find Brother Genitivi and you get some pretty cool characterization choices regarding whether or not you let him go to the temple with you (truly, all throughout this quest so far have been a lot of cool intimidate/persuade options).
When you finally get to the temple, yeah, for a while it's just a regular dungeon. But the story picks back up again when you meet Kolgrim, who gives you an offer to become a Reaver by defiling the Urn. Which, by the way, can cause two companions to attack you.
Another great part of the quest is speaking to The Guardian. You get all sorts of interesting philosophical dialog choices here. There are riddles to answer, the game makes references to your character's origin. There was even a puzzle! It was great.
So yeah, I don't know what game you played, but the Urn of Sacred Ashes quest is not a fetch quest. It's a very engaging quest of its own that has implications on your character, your companions, and the main plot (e.g., healing Arl Eamon). Like my post said, just because you "fetch" something does not mean the quest is a "fetch quest."
The Urn quest is one of the worst quests in DA:O. You get a gold star for enjoying it, but your subjective rhetoric like "wonderful atmosphere" is just that.
The Urn quest is incredibly linear, with one major decision branch and companion quest triggers at a specific point.
The quest always starts the same way: you get told in no uncertain terms that you have to get and fetch the ashes. You then begin your wild goose chase in Denerim. And the entire quest is literally a line until you to that moment, besides the backtracking with Weylon.
You only get to Lake Calenhad (a) if you don't have any speech or cunning with Weylon (and let's say that for some reason someone doesn't) and (
don't explore every inch of that house to loot everything that isn't bolted down to discover the corpse. But pretending that you don't do any of that, you then get to backtrack to Lake Calenhad before you go back to Denerim to confront Weylon.
You get Haven, and it's literally a straight line up a hill to a church. You get to the temple, and it's a straight line through the temple - though you do have to backtrack a bit and go through a bunch of rooms to open up the temple. You get through the temple and it's a line to Kolgrim.
At this point, you have the same choice you always get in DA:O - side with the "evil" guy (or in this case the insane unhygienic hermit living in a cave) or the "good" guy (in this case the spirit/demon whatever in the urn, which you technically don't know about). If you side with the "evil" guy, some of your companions attack.
You then get the ashes - regardless who you side with nothing changes in the main plot - and then everyone totally forgets you found the literal ashes of the Jesus-equivalent of Thedas. You showed up with the Holy Grail and everyone just shrugged their soldiers, thanked you for the 50 elfroot, and the game went on like none of that ever happened.
This is a fetch quest. There's lots of dialogue as part of the fetch quest. And you get to side with two different people in the mid-to-late part of the fetch quest (depending on what you count Kolgrim) but it's nothing more than an extended fetch quest.
The problem with DA:I's quest isn't that they're fetch quests. It's that they're **** fetch quests.