This is a good question. If you think about Plato's Republic, then you will realize that he believes that certain people should rule and other should not. Of course, it is the philosopher-king that should rule, but this is inherently problematic for the Occupy Wall Street (OWS) movement, because they do not want an small sliver of people running the country and the rest to follow. Their point is that masses should have rights. Keep in mind that Plato does not espouse a democracy.
When we move to Aristotle, there are some element that are attractive to the OWS movement, such as Aristotle's dislike for excessive capitalism and his theories of moral virtues. However, the OWS would never approve of Aristotle's strong insistence on the legitimacy of slavery. Moreover, both Aristotle and Plato do have an elitist mentality, which is antithetical to OWS.
With all that said, the important point that OWS could get from Plato and Aristotle is that they need to some intellectual muscle behind their movement and some clear objectives as to what a good society should look like.