When given the choice to play as one or not, human races tend to be disliked by gamers because they are considered boring. People are already human in real life, so playing as one in a game seems like the less appealing choice. However, the human-only origin, the human noble Cousland of Dragon Age: Origins was anything but boring. Despite being human in a fantasy game, the Cousland origin is still the favorite of many gamers.
Fans have related many reasons online as to why the Cousland origin is their favorite. For some, the human noble origins was the best starting point to the world of Thedas. They did not yet know about the Dalish, alienages, Circle Towers, and dwarf culture, so starting as a human noble was easy to digest for a first-timer to Thedas. The story of a human noble is simple and the betrayal that occurs is also very easy to understand.
Another major interest in the origin was the role of its villain, Arl Howe. He kills off the protagonist's family and is seen later as the right-hand man to Loghain, the major villain of the main story. While all the origin stories tie into the main story at some point, the human noble is the one that really faces its drama around the same time as the main story with defeating Arl Howe and going to the Landsmeet.
Couslands are also the only ones that can become King or Queen of Ferelden by marrying Alistair or Anora. This is a very special ending that only this origin has access to. Mages, elves, and dwarves cannot become King or Queen of Ferelden, no matter their relationships or choices.
The Dog character is also a unique aspect of the Cousland origin. While all other origins meet their Mabari hound in a quest in Ostagar, the Cousland characters actually were raised with a Mabari companion that always travels with them. So they have the dog in the origin and then through the rest of the story. This makes their bond seem all the stronger, due to their history of growing up and getting into mischief together. It also drills in some Ferelden culture, in that they love their Mabari.
The most subtle strength of the Cousland origin is its pacing with the main story. All the other origins stories were highlighted in the main plot, but in a way that is a little sidetracked. While elves and dwarves are connected to the side stories of gaining allies for the Grey Wardens, Cousland's story has pacing that is very much tied to the climax of the main plot after allies are gained. Cousland's story also has a sliver of hope throughout the whole adventure, which is to find their brother and get revenge on Howe.
The pacing is so well done that many fans have wondered if it is considered BioWare's canon origin story. Some think the human noble story is cliche, but a lot of fans do not see the cliche as a weakness but as a strength of the story. After all, cliches become cliches because they work very well in storytelling. Even after Dragon Age: Origins, the Cousland story has fun moments for the player. A major one was in Dragon Age: Awakening when one of the companions turned out to be Nathaniel Howe, the son of the man that kills Cousland's family. The two have a history that can be explored while other origins do not have that kind of access to other characters.
Dragon Age 4 is in development.