"There is a hole in the ground, you've heard it's full of treasure!" For many, this is as much story as you need for a DF game. But for me, I need a be more to keep me from becoming board with the game. That goes for GMing as well as being a player.
While running the "Caverns of Chaos", I found that the only reason the players would need to go to the caves was for another payday. Sure they were helping the town, but the direct effect was getting loot! And while players like loot, the motive felt weak. Some of the he players wanted more of a reason to keep returning.
My initial solution was to create a few "quests" from towns folks who needed item X or to rescue person Y. These worked okay but became "this week's justification." Then, I created a longer quest for the players to find and destroy an evil alter.
The quests worked out fine, but looking back I think what was really needed wasn't a reason to go to the caverns, but a desire to. Perhaps if I had put more work into strange and interesting things that were there, the players wouldn't have needed a particularly strong external reason to return week after week.
What I am saying, is that Dungeon Fantasy does need story, but that the best story should be environmental. The PLACE should be the story. Strange rooms, new creatures, odd happenings, lost history, etc.
Going forward I still will have a "meta-quest" to drive the players into the dungeon, but once there, I think the real story is going to be what they find and discover. Exploration is story.