What might be a good thesis in which to write an essay based on the personal characters of Emilia and Desdemona?

Emilia is generally considered to be a foil for Desdemona in this play, where their differing characters contrast and illuminate each other. Emilia is older, wiser, and cynical about men and their desires. Their conversation about fidelity in Act IV, Scene III is particularly illuminating. Desdemona, young and naive, does not believe "there be women who do abuse their husbands" by being unfaithful to them and insists that Emilia herself would not; Emilia scoffs and describes infidelity as "a small vice." Elsewhere in the play, Iago suggests that Emilia has been unfaithful to him with Othello. Emilia seems very aware of the lowly way in which women are regarded in Venetian society and declares that it is a husband's fault "if wives do fall." Ultimately, it is Emilia who unmasks Iago as the villain he is and who comes to Desdemona's rescue, albeit too late, when Othello has smothered her.
A thesis for the two of them might, then, focus on the question of why these two women characters are written together in the play. Does Emilia's cynicism help us to appreciate Desdemona's youth, naiveté, and innocence? Could Desdemona have avoided her fate if she had been more like Emilia, believing that Othello wanted nothing more from her than sex, rather than trusting in his love? What about the fact that, in the end, both the cynical wife and the idealistic wife is killed by her own husband—perhaps this illustrates the powerlessness of women in the society of the play, whatever their personal natures.