Lazenby only wanted to do the single Bond movie. He eventually came to regret that decision because everybody assumed it was the studio's choice to replace him so fast.
Moore might have been able to play Bond rougher than the movies they gave him, but I don't see him pulling off anything near a TD or DC level of roughness. I think the basic complaints about RM playing the role are valid even if the movies he got were an equally big factor in it.
Look at DC. He comes off like a working-class pub brawler uncomfortably stuffed into the Bond role. His movies are emphasizing that tone, for better and worse. The movies & actors tend feed off each other and lean towards a certain tone.
That's a good point. I actually think that ties neatly into Bond's (literary) background. As I recall, Bond is supposed to have been a scion of Scottish nobility, but somewhat impoverished Scottish nobility. He went to public school, but never really fit in. I seem to remember Vesper pretty much nailing him on all of this when they're having a drink together, and basically guessing at his background, all pretty accurately. It's not exactly that he's "working class" but rather that he looks at the privileged classes with a degree of disdain for their inability and unwillingness to get their hands dirty.
Again, it's one of the things that makes Bond's character so interesting -- when they let it shine through. He disdains the people who won't get their hands dirty, but at the same time, he has a LOT of self-loathing for the job he does (which is pretty much the epitome of "getting your hands dirty"). Bond's job involves lying on a regular basis, as well as legally sanctioned murder. He may have a licence to kill, and he may be good at it, but that job leaves a stain on his psyche and his soul. And at the same time, it's thrilling and he loves it, which only further makes him feel conflicted if not outright disgust with himself. And all of THIS is why he indulges in the gambling, the women, and the deep knowledge of the "finer things in life" like fashion and alcohol. All of that is a distraction and the only ways that he can feel like the world isn't simply a dark pit full of vicious, murderous men...like himself. Bond is a deeply, deeply conflicted character, and a far cry from the glamorous playboy cartoon character of the Moore era (and which influenced the Brosnan era, as well).
It's that side of Bond that comes through loud and clear in the novels, and which comes through subtly in Craig's performance. Other actors (like Dalton, Connery, and even Brosnan at times) got the ruthlessness of the character, but really, only Craig has gotten the remorse and self-loathing part. Actually, Brosnan very occasionally allowed Bond's mask of cold ruthlessness to slip, but his scripts didn't give him a ton to work with (although my sense from interviews is that he really wanted more of that).
Now, I also get that not everyone WANTS a Bond who is a ruthless killing machine, nor a deeply conflicted psychologically damaged individual. I think, however, that you CAN have both. Bond can maintain an exterior of cool detachment in many of his scenes, giving way to utter ruthlessness and violence in others. But I think you also need to balance those moments with ones where we see the impact of his life on Bond. The pain he feels when, for example, he has to stand by idly while the villain kills the woman who just helped him that Bond COULD have saved...if not for the requirements of his mission outweighing that. You can show Bond's disgust in moments where a kill was unfortunately made necessary or where he cannot stand by and help an ally (like Remy in QoS), or where he has a quiet moment in the film and feels the weight of his actions. These can be done overtly, but they can also be done subtly enough that the people who JUST want the cool action hero will largely ignore them.
To me, that's the great strength of Craig's portrayal. Even in a film like Skyfall, which was a LOT closer to a traditional Bond movie than we've seen in his tenure, those things came through in Craig's performance...but they weren't lampshaded the way they were in Casino Royale, or the way they have been in past Bond movies (e.g. Tomorrow Never Dies, Goldeneye). Between Craig and a good editor, you can show something as simple as Bond simply working a jaw muscle and holding a look for an extra beat, while otherwise appearing impassive when these things happen, and it still gets across the sense of frustration, pain, remorse, etc. But it does so without, say, having Bond weep openly or say "GOD I HATE MY JOB" or whatever.
One of the other things I've most appreciated about the Craig films is the character growth they've shown with Bond. At the start of Casino Royale, he's a rookie 00, having just made his second kill in the line of work (with his first resulting in him vomiting afterwards). Over the course of the film, we see Bond toughen up, let down his guard, wind up betrayed, and fully put on his armor by the end of the film. When he shows up in his 3-piece holding the silenced UMP-9 and saying "Bond. James Bond," it's Bond fully putting on his "costume." From that point forward, you can have Bond occasionally show cracks in the armor, but you can never let him drop it completely the way he did in that film. And yet, that film, for the current iteration of the franchise,
needs to be a touchstone for all future depictions. We need to remember where Bond came from and who he was, so we can understand who he is now, even if he becomes a guy who can give an ironic look in a dangerous situation. We need to know that he does this stuff not because it's a wink to the audience, but because it's part of Bond's character, part of his armor and the mask he wears to help him weather this horrible job he does. Bond can have his lighter moments, but they also need to be grounded in the humanity of the character, or else the whole thing just becomes a boring power fantasy built on cartoonish caricatures, like a badass version of Austin Powers.