What went wrong? This is the series looking back for the first time. Following the Lazenby debacle (as it was seen at the time) the producers were clearly hoping to smooth things over with audiences by doing Goldfinger again: Sean's back, Shirley's doing the theme song, Guy Hamilton's directing, diamonds are almost as good as gold, there's an even bigger laser and the original intention was to get Gert Frobe onboard as Goldfinger's twin brother.
Charles Grey's Blofeld is the series's first generic Bond villain, a patchwork of what we expect from such a role. He has no motivation and no characteristics and isn't even allowed his own name, instead taking on the name of his predecessors with no attempt at continuity other than the cat. There is a clear feeling that neither Grey nor the screenwriters believe in the character, most obviously demonstrated in his line "science was never my strong suit." (As in the line's reuse by Scaramanga in The Man With The Golden Gun, Diamonds Are Forever's only rival for the position of worst film in the series, it's a blatant admission that the villain has no clue what he's doing.) Auric Goldfinger had that wonderful little moment when, after Bond told him he enjoyed his briefing, he gave a little schoolboy grin and said "so did I," turning a plothole (why tell those mob bosses his grand scheme if he was going to kill them?) into a richly satisfying character detail. Telly Savalas's Blofeld had that wonderful way of holding a cigarette vertically (perhaps borrowed from Hitchcock's instructions to Martin Landau in North by Northwest) and his pleasingly bizarre demands for recognition of his title as a result of his evil genius. Pleasance's Blofeld had the piranha fish and the line "if you'll excuse me I'm about to inaugurate a little war". Grey is stuck walking around an oil rig that looks like a dull oil rig, pointing out that Bond's "pitiful little island hasn't even been threatened yet" and that "if we destroy Kansas the world may not hear about it for years." Nice lines, but all very half-hearted.
Tiffany Case is also the series's first badly-written main female character. Neither Tatiana nor Domino were well-cast, but they were at least efficiently written, both making their own choices and rescuing Bond at the end instead of vice versa. Tiffany lounges around like something out of a Matt Helm film, adding little to the narrative and giving Bond and Blofeld opportunities to sneer at her for being stupid. One particularly unpleasant detail that will recur in The Man With The Golden Gun is in the focus on Tiffany's bottom as an index of a deeply misogynistic view of femininity: it's something we're invited to ogle, but it's also something that throws its owner's lack of brains into relief. "Such nice cheeks, too - if only they were brains," says Blofeld after Tiffany, having put the wrong tape in the machine, tries to correct her mistake but is betrayed by the bulge of the hidden tape in her bikini bottoms. The film does nothing to leave itself unaligned with this toxic view. Tatiana and Domino got to shoot the main villain, Tiffany isn't allowed to fire a gun without the backfire comically sending her off the end of the oil rig. It isn't Jill St John's fault, but the series's portrayal of women takes a nosedrive here.
The film might have worked had it stuck with the curious obsessions of its first half, before the laser plot is dragged in. It's been pointed out before that the theme of counterfeits runs through the film: fake Blofelds, fake diamonds, fake fingerprints, fake money, fake wigs, fake lunar surface, fake voices. Had the script stuck with this, perhaps along with the diamonds it might have given the film an aethestic, as gold did for Goldfinger and voodoo would for the next film, Live and Let Die. It's interesting that Live and Let Die, a script solely by Tom Mankiewicz (co-writer on Diamonds with Richard Maibaum), works precisely because it avoids dragging in a full-scale "Bond-villain" scheme, preferring to focus on thematic concerns and a central set of motifs rather than making sure the script had everything audiences expected from a Bond movie. Maibaum never understood this, calling Live and Let Die "a lousy cooking-dope-in-the-jungle kind of movie". Similarly, Mankiewicz's version of The Man with The Golden Gun sounded a lot more promising and unusual, focusing entirely on a Shane-style duel between Bond and a single nemesis, while Maibaum, brought in to redraft, evidently felt Scaramanga required a solar power plant to qualify as a Bond villain (he also later said of his rehashing of Goldfinger: "the villain's caper in A View to a Kill is one of the best we've had, one of the most unexpected and one of the most exciting.) Perhaps a solely Mankiewicz-written version of Diamonds would have been more interesting.
Of course, that wouldn't explain why Guy Hamilton's direction is inspired in the next film and slack here. Diamonds are Forever sees the series struggling to adjust to the absence of Peter Hunt, director of the previous film and editor of the five before it. The Las Vegas car chase and oil rig finale are so unexciting that it is hard to believe you are watching a Bond movie, and the moon buggy chase is also slack, seeming to think that the comic sight of a moon buggy is enough to entertain the audience and will suffice over any attempt at pace or tension. The blunder that ruins the otherwise-good fight with Bambi and Thumper- they inexplicably cease to be strong and become weak enough to hold down when in water - seemed unthinkable under Hunt's watch.
The superb Wint and Kidd (Bruce Glover and Putter Smith) are, along with Connery's return, why there is a danger of remembering this film more fondly than it deserves. They manage to be funny and sinister at the same time. Their distinctive way of speaking to each other is a wonderful cinematic device, and makes them memorable in a way that the villains in the Craig movies sadly aren't. Their being gay is used to add verisimilitude rather than to demonize them as sexually other: the only slight touch of homophobia comes in the gag at the end when Wint gives a cry of pleasure after Bond grabs his trousers. It's their film, but sadly they're welcome to it.