Masculinity
Aristophanes' play is his way of calling to center stage the men who were in his time the members of the Assembly. To Aristophanes, they were not truly 'masculine' men, meaning that they didn't displayed qualities that were necessary in order to lead the people. They instead created laws to suit themselves and what they thought was right rather than what was actually good for the growth of the city and its people.
Identity
The women, led by Praxagora, dress themselves in the cloaks of their husbands and wear fake beards in order to fool the members of the Assembly. This concept is used by the playwright in order to represent the inability of the Assembly members at the time to recognize who is who, in essence that they were willing to believe anyone who stepped upon the stage without examining them more closely to see that they and their motives aren't what they appear to be.
Republic in Trouble
This theme has to do with the reality that the Republic at the time of Aristophanes was in trouble, and in order to ensure it survived the Assembly was willing to do anything in order to make that a reality. Thus, the effect of the women's regulations are seen at the end of the play. There is an atmosphere of the people going wild. They've created a system of even more chaos in their begging for a new way by rushing into a hasty decision.