Unless Bond later undergoes a more radical transformation than I can imagine, Fleming's Bond just doesn't strike me as "cool" at all.
Fleming's Bond has always struck me as an incredibly cool, film noir-esque character. He's always been cool in my eyes - and I've never seen him as anything else. It's that Cary Grant or possibly Humphrey Bogart sort of cool. It's just an aura of being a man's man who's tough and elegant at the same time, who's confident and collected.
I think that's partially what it is - Dalton's Bond always felt very tense to me. There wasn't the ease that I expect Bond to carry with him in his persona.
While he's no Connery (who himself was only modestly "cool" in my book, for reasons I have expounded upon elsewhere), Dalton still manages his own coolness in a lot of dialogue scenes, many an action one, and generally anytime he's pissed off or focused. He falters only when it comes to the natural humor, itself an element of "cool," and his relationship with the ladies, which was humble, whether he was being romantic (TLD) or just getting it on for fun (LTK).
Which is a pretty big fumble. He does okay for himself, and he's hardly painful to watch or anything, but he doesn't have that innate collectedness that I think Bond should have and his rather poor dealings with the ladies do a lot to damage him.
Furthermore, he just doesn't fit that noir-styled, pulp hero vibe I get from Fleming.
To tie that into the thread (barely), it's the same kind of "cool" I could have seen a Neill-Bond have.
Honestly, I think Neill's Bond would have probably been a little more... enjoyable and humorous than Dalton's ever was.
Moore...well, you gotta love him, but he just had it here and there, if he was lucky.
Moore had the "I am a superhero" kind of coolness. He was never thrown off - he was always there, on the top of his game, and for that he has to be appreciated. His Bond was very much clearly more a cartoon than the others, but it worked and came with its own brand of cool.
