I'm on the fence quite a bit when it comes to Hamlet, but G. Wilson Knight's interpretation of the play is a fair representation of my views towards the play as well. The entire play is centred around "death"; the death of Hamlet's father, the confrontation of the ghost to hamlet (death in it's purest represenative form), Hamlet questioning his own existence (contemplating suicide). Due to these rather unfortunate and life-changing events, Hamlet himself changes. The man he was in the beginning or even before becomes extremely altered. He dives deeper into a state of melancholy, whether it be real, or his antic disposition, who truly knows. As Knight puts it, Hamlet has "soul-sickness" and becomes completely obsessed with death; plotting his revenge against Claudius, his father's death, his own suicide, etc.

I believe this interpretation has brought me closer to the question of "Why must Hamlet die?". Although we never want our protagonist to die, it may have been the best method of treatment for Hamlet's state of self. Throughout his first three soliloquies, he is constantly contemplating what is the best thing to do, to live or to die? To kill or to not? In the fourth soliloquoy he realizes how disgusted and ashamed he is of his inability to commit to one plan of action. Although the idea of lack of Catharsis is present, it is my belief that Hamlet must die as to cure his "soul-sickness" and to put his unsettled thoughts and conscience to rest, to ultimately relieve him of the idea of death by presenting him with his own.