Had George Lazenby stayed
Had he stayed as Bond, I think his acting would have greatly improved and would have grown into the role, "Diamonds are Forever" wold be a lot different comparted to the original TL, Peter Hunt would be back in the director's chair and Telly Savalas would return as Blofeld, could have the same story, but would be a lot better with the revenge storyline. Also Norman Burton as Felix would be recast with David Hedison, I do think he and Lazenby would have worked well since Laz is Australian and Hedison is Armenian-American and would fit in the right age group. The rest of the cast would be the same, but the Sprangs would be included.
Lazenby would continue with LALD where he would face off against Yaphet Kotto's Kananga. Lazenby's staying on would have proved that while the spy genre ended in 60s, with no more Our Man Flint Movies, or Reckoning Crew Movies and shows like Get Smart and Man From UNCLE would be off the air, Bond would have been the only spy series still going and would be influencing other bog movies at the time. LALD would be influenced by Blaxploitation movies like "Shaft" and "The Man with the Golden Gun"was influenced by kung fu movies, which would have suited Lazenby. As for TMWTGG, it would be a better movie as it would suit Lazenby's Bond, his portrayal would be different to Bond's where he would be more a cockier character, but would have emotions, the dojo scene would even be suited for Lazenby's Bond. Also I could picture him going up against Christopher Lee. But this film would sill be a weak point and for Lazenby. I do think that in this timeline Saltzmann would still leave the franchise after selling his shares (50% stake) after making making some investments that didn't pay off. A three year hiatus still happens, Lazenby while signed to his seven picture contact wants to leave so he could do other things, but Cubby Broccoli makes a deal with Lazenby that he could get out of his contact after his fifth movie which is "The Spy Who Loved Me", which would tie in with the continuity of Connery's Bond movies and Lazenby would go out on a high. The series would be saved, he left it in an amazing space for someone new to come in.
With Lazenby gone, the search would begin for a third Bond actor, with Moonraker intended as the next, I think the names considered would be Michael Billington, Lewis Collins, Ian Ogilvy and Timothy Dalton. If Billington or Ogilvy had gotten it, either one would do four movies before Dalton comes in 1986.