Was Shylock more wronged against than wronging.... was the harm done to him more than he did to others?
The Merchant of Venice - Answer to be taken only from Act 4 Scene 1- (nothing before or after that)
You must be careful with any work of literature, but certainly with the script of a play, when you attempt to isolate a scene or event from the rest of the action. It all hangs together to create the whole, and it is nearly impossible to do justice to the play or the character of Shylock in considering one scene as if it existed as a mini-play all by itself. How does this assist in understanding the whole work, which surely must be your aim?
That said, when looking for a definitive answer as to whether a character in a play is wronged or, conversely, in the wrong, you should search for an objective rather than subjective answer (there will always be numerous subjective points of view on any subject). The most objective criteria here is: What is the character's function in the plot, the structure of the play?
In The Merchant of Venice, Shylock is the comic villain. This simply means that, structurally, his actions provide the dilemma for the major characters in the play. In this case the story of Antonio, Bassanio and Portia is most affected by Shylock's actions. Dramatically, he serves the structure of this play just as Don John does Much Ado About Nothing or Malvolio, Twelfth Night.
The pertinent question to ask is not whether you feel sorry for the comic villain, but rather what needs to happen in the play for him to fulfill his function dramatically. In this case, Shylock gets his just desserts. He asks for his pound of flesh, and since he has no way of being exactly sure that he will take only one pound (no more, no less), he must forfeit his revenge. His being "punished" in this way, while the major characters of the play prevail, is completely on target for the structure of a Comedy. It would also be appropriate, structurally, for Shylock to be reconciled to the social order of which he is a part (Christian World) by joining them, hence the required religious conversion.
For a true objective appraisal of the events of Act IV, Scene i, you should look no further. Now, if you'd like to debate emotional, subjective reaction to these events, especially in the light of our 21st century points of view on religious tolerance, I'm sure you could invite quite a lively discussion.
If we may use only Act 4, Scene 1, then I propose that Shylock is indeed himself more wronged than any other party is wronged by him. The scene illustrates Shylock’s cruelty, his mercilessness, and his ruthless pursuit of what he thinks is his in spite of morality, but it also illustrates the bastardization of law. Shylock, a Jewish man in a nation of Christians, cannot get a fair trial. Who is the arbiter of his justice? A fair and impartial legal mind? No, the wife of the opposing party's friend. Is this conflict revealed to Shylock? No, the truth is concealed from him. Is the prince impartial? Not really, it is quite clear that he sides with Antonio, even if he cannot come up with a way to protect Antonio on his own. So can Shylock get a fair trial? No. Shylock's plight in scene 4 reveals that a Jew surrounded by Christians cannot receive justice.
Much as we may dislike Shylock for his bloodthirsty attitude, the wrong he seeks to perpetrate is only available to him through enforcement of a lawful (if brutal) contract, a contract Antonio agreed to. The other characters are all arrayed against him and they use a legal technicality to destroy the fundamental purpose of the bond Antonio agreed to. Shylock becomes the target for a conspiracy to pervert the law and punish him for seeking its justice. Now, if you consider the entire play, I think we could all agree that Shylock gets what is coming to him. He who lives by the sword, dies by the sword.
Beyond the proper dramtic function that Shylock has a character and beyond its role in whole dynamics of the play, Shylock shouold also be looked on as what it stands for: a Jewish man, and that means - in Shakespeare's time, a man to be scorned refused and discriminated. This is what Shakespeare wanted his audience to see, at least on the surface.
However, and this is not only for us, people of the 21st century, the character could have an additional thematic function: to make think about themes such as humanity, tolerance and equality. This is exactly what Shylock does through his well known monolgue "Hath a Jew not eyes..."; his words induces us - and probably also Shakespeare's contemporaries - to change our opinion and judgement and to release a different kind of catharsis which is not simply caused by the satisfaction of witnessing Shylock's punishment but by the feeling that, maybe, he has been offended as a human, learning to offend because of ignorance and intolerance.