Think about the idea of “justice” in this unique mystery. Did the characters “get what they deserved,” or were any of them punished unfairly?

This question calls for your opinion, there is no right or wrong answer. In my opinion, there's a reason we have court systems, and a judge should understand the reasons and process better than anyone else. That isn't to say that verdicts are always correct. None-the-less, Judge Wargrave's actions weren't based upon justice.... they were based on vengeance.