Do Greek myths offer one cohesive vision of the role of women in Greek society, or is there different roles women play?
I think that there are many different conceptions of women offered in the Greek myths. This is similar to how there are many different conceptions of men offered in the narrative of Greek mythology. The reality is that women, like men, were punished for transgressions that would be perceived as offensive to the immortals, and rewarded for displaying attributes that pleased them. For example, we see hubris punished in the form of Arachne in attempting to "one- up" Athena. Yet, we see Baucis being rewarded for her sense of charity and generosity to her guests. In visions like these, what it means to be "woman" is different. The implication here is that Greek myths did not care so much for gender as much as use of mythology as a moral platform which to demonstrate right and wrong elements. Greek society had marginalized women to a great extent, in terms of denying them political and social power, so that it would seem highly unlikely that they needed to use the mythology as a way to display their attitudes towards women. This was already clear in their social order.
Women play different roles in Greek myths, suggesting that women played various roles in Greek society.
Among the most famous female goddesses are Aphrodite, the goddess of love; Athena, the goddess of wisdom and war; and Artemis, the virgin goddess of the hunt. By just comparing these three female figures, we see startling differences in their roles: Aphrodite is a sensual being interested in the erotic and has many lovers, Athena is revered by heros and philosophers and is depicted as a counselor in myth, and Artemis is revered for her purity as well as her skill in hunting and is thereby depicted as an Amazonian-type goddess.
Greek myths offer various prototypes of women that have propagated in subsequent western literatures, and are often invoked by poets. The very passionate Aphrodite and the chaste Artemis may be seen as a binary within both Greek myth and later literatures, presenting women as one of two extremes. However, as can be seen by Athena and others, there is nuance Greek myth's depiction of women.