A feminist writing about Hamlet would argue that the women of the play are really only there to show us more about Hamlet. They are useful to show us how Hamlet reacts when in love and to show us his relationship with family. Gertrude is an insecure woman who marries Claudius perhaps to protect her own status in the Court. Ophelia is very much under the thumb of her father Polonius and is expected to obay him, even to what she says to Hamlet, a man she supposedly loves. The rejection of her by Hamlet, when he is aware that they are being spied upon, and the murder of her father turns her insane. Either Gertrude or Ophelia could have been more independant minded, but neither really takes a stand as themselves. (Unless we consider the way Ophelia speaks to the court when she is 'mad' as her true feelings and voice coming through) Of course the play is called 'Hamlet' and the dilemma he finds himself in as his world falls apart is the central theme of the play. He is also a factor in the deaths of the two women he undeniably loves and this is part of the tragedy of the play.
Both Ophelia and Gertrude are very much representive of women in the Renaissance. Each is under the direction of their "betters" - father, brother, son, or husband. They are portrayed as subject to their feeble wills; Gertrude's need for a husband and her lust for Claudius, and Ophelia seems to be unable to exist without Polonius as a guide. She cannot replace him with a husband and therefore descends into madness.