Sir Roger Moore was the James Bond that I grew up with; his take on the character was oft-derided but it was perfect for the times.
To say that Bond should have been cunning, ruthless, and humorless in the 1970s was to ignore the overwhelming importance of male bravado and self-awareness of the times. This was the decade that made stars out of complex characters (DeNiro, Pacino, Hoffman) and less than complex fellows (Eastwood, Reynolds, Bronson). You could not have made Bond like any similar character from American cinema, nor could he have had the detached, monosyllabic approach of international films. Bond had to be a global star, able to bridge all of the different genres of film. He had to be able to do dry humor, heart-stopping action, clever romance, and political intrigue. He had to be able to save people, kill people, and mock people, often in the course of a single action sequence.
That meant finding a British actor with serious theater chops, which is what people still do when they need someone who can truly inhabit a character. Michael Fassbender is the Roger Moore of our time, but, really, he's just another version of Moore churned out by the wonderful schools that teach acting in Britain. You can definitely see Fassbender becoming one of the greats and surpassing quite a few great actors, but he's following the template that Moore helped create.
In his day, no one was better than Roger Moore at being everyman and superman at the same time. He had to portray a character that was marketed and sold to the vast world audience of the time. He had to be the actor who could open a film in London, Rome, Los Angeles and Tokyo and few people have ever been able to do that. The universality of his portrayal does not dim with age. You can laugh at how camp it was, but the whole goddamned 1970s was a campy affair on purpose. At no point were you ever not able to believe he could do what he did. That was what made him great.
The Bond that Roger Moore gave us was sharp, sly, quick and capable. He was very much of his time, and we do his performance a disservice by thinking he had to act like the action figures of the last thirty years or so.