One quite interesting detective quest has to do with a burned down inn, at the border between the swamp and the Barrens. There are three "clues" hidden in the inn, a shield, a tiny badge, and some hoofprints. I had found the shield, but the other clues I only found after reading about them on Thottbot. Each clue leads to a quest, leading to the perpetrators of that crime. Unfortunately the series ends with a dud. After you did everything, you are told to bring the black shield to somebody in Thunders Bluff, for the final revelation of the mystery. And there you hand in the shield, get a tiny xp reward, and the quest abruptly ends without explanation. Seems a bit unfinished. Maybe you would get more information if you did the Alliance side quests from the same three clues, but my druid only found the black shield at the time, and now his account has expired.

Maybe the reason why the Dustwallow Marsh are a bit underpopulated is that this is not the only bad quest in there. There is a guy in a hut in the swamp, "Swamp Eye" Jarl, who gives three quests which don't make much sense. First he wants three soothing spices, which you have to buy from a vendor, and the reward is only some food without stats. Then he wants 40 spider eyes, but he is talking crazy, and you don't really know what for. And then he wants an expensive smithed sword for the third quest. I declined that third quest, because I knew how valuable the sword was, and the reward he offered was worth a lot less. But I checked on Thottbot if there was another quest behind that, which would explain and reward a bit more, but there apparently isn't. Simply a badly written series of quests. It actually speaks for the otherwise high quality of the World of Warcraft quests if the bad ones are jarring so much.

One very nice, hidden, level 40 quest is in the Dustwallow Marsh. There is a hut with a guy named "Swamp Eye" Jarl, who gives very bad quests (best avoid doing those), but in his garden is a freshly dug grave. When you click on it first, you find a hand. Bring the hand to Brackenwall Village gives you a reward, but no clue that the quest isn't finished. You need to go back to the same grave, and by further digging find a head. From that starts a quest where you boil the head in a troll voodoo cauldron in Grom'Gol to make him speak, which then gives you a quest to find a necklace from crab men in Dustwallow Marsh. After handing the quest in at Brackenwall, you are sent to Orgrimmar, where you get the choice between two very nice blue rings. Well worth it, and I guess not many people did that quest.