I guess it all depends on who is doing the judging.
The Duke has allowed Vienna to get out of hand, at least at least morally speaking. The red light district is wide open. Question, can morality be legislated? We try but is it a legal matter or one for each person and their belief system? By putting Angelo in charge, the Duke attempts to right the perceived wrongs in his society. Of course, Angelo when given the power, misuses it.
It is really clever how Angelo gets caught in the bed trick. He was so quick to punish Claudio for premarital sex when he, himself, lusts after Isabella. By being forced to marry Mariana, an ironic sense of justice is the result.
The release of Claudio is just since he was only guilty of doing what had become accepted practice in Vienna. All along he had intended on marrying Juliet.
If prostitution is a crime, it could be said that the imprisonment of Mistress Overdone is justice.
Lucio is another example of ironic justice. He doesn't know when to shut up and being forced to marry a prostitute is a kind of justice for this strutting popinjay.
The open ending leaves the decision in the hands of the reader or production company. Do the Duke and Isabella get married? Does Isabella return to take her final vows? Does the Duke learn his lesson and become a better leader? Shakespeare doesn't tell us.
What is justice depends on many factors and changes from culture to culture. What is legal and acceptable in one may not be in another. This is also true depending on when in history we are talking about. We still struggle today with morality and legality.
Not completely, or at least, not by modern standards.
Mistress Overdone might; prostitution is still considered a crime, and she is jailed for it.
Isabella's virtue is rewarded.
Vincentio mostly gets his reward for being a nobleman, though you might argue that his quest for good government deserves something.
Angelo gets far too light a punishment; he deserves harsher for his abuse of power.
Lucio mostly sins by accident; his punishment seems overly harsh.
The play Measure for Measure by written William Shakespear does not with its title.
Angeke who considers himself a man of virtue who works with the law and punishes anyone who offended the law is not given a fair share of punishment when he breaks the law himsslf. he is only forgiven.
A woman like miss overdone who out of mercy takes care of Locio's illegal child is rather put in prison bacause she did not get anyone to plead on her behave.
Isabella who sees his brother as a friend when it happended that she pleads for the her bvrother Claudio.
Duke Vincentio uses Angelo as a scapegoat to correct the corruption caused by his dukedom. At the end Angele is the only one who bears the disgrace and punishment that the corrupt administration of the duke has created.
Lucio who bravely tells the disguised duke in the face that the former duke was not brave enough to correct the social vices in his kingdom by comparing the administration of Angelo to that of the former duke, in the end he is only punished for saying the right thing. But those who committe crimes are left to go free.
The duke and Isabella come together to help Mariana committe fornication which the law forbids but in the end, both are set free and even rewarded.
Hence we can conclude that the purpose for which the duke appointted Angelo is not achieved, since he forgives anybody who committed a crime in his absence.