What we, the fans, think Merlin is about, and what the producers, the writers, and the actors think it’s about, are two entirely different things. And that’s true whether you ship Arthur/Gwen or Merlin/Arthur. I think Bradley summed it up well with the line “before they were famous”. The goal of the show’s arc, one way or another, is to get Merlin, Arthur, and everybody to the point where they are ready to become the stuff of legends.