But then he rolls badly several times on coercive PM rolls, and the character succumbs to alcoholism. A similar problem can occur with representative PM's, in that they can oversimplify the inner life into a few numbers. When depressed, the alcoholic has lower willpower. However, the mechanic mixes up his manic phases of energy with his times of lucid, self-analyzing thinking. Most PM's attempt to reduce personality to simple numbers and keywords.
People can be greedy for a variety of things, with varying motivations.
The more personalized each stat becomes, the more you rely on judgement rather than on the mechanic. Another problem is GM vs Player visions of the character. GM-moderated PM's establish the GM as the authority on what a character will do in certain situations. By taking this out of the hands of the player, it moves the responsibility. A player will know far more about his character and thus, if trusted, is better suited to have the final authority.