What is one to make of Oliver Stone? Usually, Hollywood stars make asses of themselves as wanna-be artists. They work well within formula but lose themselves outside it. Stone is the opposite. He is best in artistic mode and falls flat with formula.
Stone's villains are usually the most interesting. Stone cannot endorse their positions yet is too much of an artist to simply caricature them as monsters. Also, the egotistical side of Stone makes him, at least subconsciously, identify with power-hungry men. So, the character of Gordon Gekko shines in WALL STREET. He's a crook, a shark, but also a creature of powerful instincts, insights, and talents. There is magnificence in his greed, a real passion for life than mere greed for money.
One could argue that Gekko is too sensational, especially with handsome Michael Douglas in the role. Good or bad, he is the star like Hannibal Lecter is in SILENCE OF THE LAMBS. He is above conventional morality, beyond good and evil.
Stone succeeds with Gekko because he is artist enough to see Gekko from all angles, ranging from disgust to admiration. Where Stone falters(in this movie and in others) is in featuring the Good Guys, the representatives of Labor. Stone goes formula and gives us trite speechifying about the Common Man. It's like Stone is on auto-pilot doing assembly line screenwriting. It is by rote than wrote.