Greene can be summed up in one word - corrupt. With him, there seems to be no problem that cannot be bought off, save, of course, James Bond. Unusual for a Bond villain - we tend to think of them as driven individuals prone to eliminating their problems literally and killing their adversaries, focused only on the goal of blackmailing or dominating the world.
On the other hand he has a cruel streak - what kind of man would "make a point" by drowning a pretty young woman in crude oil, leaving her naked body in Bond's hotel room? (answering my own question, one who went to see the film "Goldfinger" in his youth!
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)
Amalric is a good actor, and I agree with the point one contributor here has made - if a film is made of the highly controversial life of Roman Polanski, Amalric seems an obvious choice for the role.
Not a "classic" Bond villain - maybe because he doesn't conform to the cliches we expect of them - but probably a bit more realistic than most.