The Problem with Roger Moore is Not Roger Moore
One of my biggest frustrations with the Roger Moore era is the way in which the Bond producers misused Roger Moore's talents. Rather than placing Moore's Bond in serious films and allowing his natural charm and charisma to shine through, the filmmakers instead decided to put him in action-comedy type films that cheapened his performance. As a consequence, the Moore era tended to be very hit and miss.
In my opinion, the film that showcased how Roger Moore ought to have been used was Live and Let Die. For one thing, it treats its story and subject matter very seriously. As a result, we as an audience are willing to accept some of its more outlandish elements - particularly, the voodoo and Solitaire's precognition. Take the boat chase as an example: we are under no illusions about how much danger Bond is in. (If anything, Sheriff Pepper is inserted into the chase to ease our tensions).
Most important, however, is the manner in which the filmmakers handle Roger Moore. Moore's portrayal of Bond in this film is different to his successive films. In this film, Moore's portrayal of Bond in Live and Let Die can accurately be described as superficially charming, charismatic, witty, stylish, sophisticated, and elegant. It is easy to believe that Moore's Bond could seduce a beautiful woman like Miss Caruso or Solitaire with relative ease.
As Yaphet Kotto opined in "Inside Live and Let Die": "you got more of the feeling of the English gentlemen with Roger Moore."
Furthermore, unlike future Moore films, Live and Let Die doesn't try to turn Bond into a "good guy." In the film, Bond is as much of an unrepentant bastard as he is in the Connery (or even the later) films. In one scene, Bond threatens Rosie Carver, a double agent, with his Walther PPK. In a later scene, when he and Solitaire have escaped from San Monique, Bond tells Quarrel, Jr.: "this is a valuable piece of merchandise we're carrying which, with any luck, they'll want back."
It would have been nice if Moore had maintained the Live and Let Die version of Bond throughout his tenure (or a variation thereof).