I've been asked more than once, "What is Ophelia doing in this play? What is she adding?"

I think it's a lot more than the pathos of a young woman in love with love being wronged by a man with more on his mind than how much he may love her.

Consider the parallels between Ophelia and Hamlet: Both have only one parent (of the opposite sex) still alive.

Ophelia is (probably due to her own insecurities) mistrustful of Hamlet's feelings for her. The men whom she's used to trusting (her father and her brother) both tell her in no uncertain terms that she should not trust those feelings.

Hamlet is mistrustful of Ophelia's feelings for him. We are not aware of any point at which she has said that she feels he's right about his mother's and uncle's betrayal of his feelings about his father. When she has a chance to stand up for him (when she's asked to act as bait for Claudius' spying on Hamlet), she does not say, "No, I will not, I love him"--either publicly or privately. When Hamlet asks her, "Where's your father?" she doesn't point to their hiding place, wink a few times, and say, "At home, my lord." I don't want to say that I blame Ophelia for her actions, because I think it's a different issue--she's in over her head with the schemers who surround her.

The long and short of it is that I think there is a strong parallel between what Hamlet is thinking and feeling about his rotten life and what Ophelia actually goes through.