Many critics agree that Malvolio, and more specifically how his character develops through the treatment of him by other characters, makes him one of the most complex and profound characters in the play. Certainly, as the play begins and we are introduced to Malvolio, he is a figure to poke fun at with his serious, "Puritan" attitudes to service and life. Certainly Feste, who could be said to be the force of chaos in the play, thinks so, with his confrontation with Malvolio. This feeling of amusement continues as Malvolio is gulled and with the famous "yellow stocking" scene, which is a sure crowd-pleaser. However, what becomes definitely more dubious is the treatment of Malvolio when he is locked up and Feste, disguised as Sir Topas, tries to convince him he is mad. This is where the audience begins to feel sympathy for him and we begin to feel the joke has gone on too far. Certainly his last explosive line in the play suggests that he is not re-admitted into the "happy ending" of this comedy, leaving us with the impression that, in spite of his faults and arrogance, he is a character who has suffered in a manner that is disproportionate to his crimes.
The above commentator rightly argues for Shakespeare’s greatness in handling the character of Malvolio. However, Maurice Charney’s interpretation also needs to be considered in this regard. While commenting about Malvolio’s gulling Charney notes: “Whether Malvolio has been most notoriously abused, or whether he is the well-deserving victim of a practical joke that explodes his vanity, social-climbing, and pretentiousness is the point at issue.” Malvolio’s gulling in Act II, Sc. v does not evoke readers’ sympathy. The sympathy is aroused when he is imprisoned by Toby and harassed by Feste. His gulling in Act II, Sc. v “explodes his vanity, social climbing, and pretentiousness”, but when he is imprisoned and further harassed, it reveals nothing. Shakespeare has probably done it only for initiating a kind of sympathetic sensation for the character. Malvolio thus emerges as the only character in the play for whom the readers laugh at first and sympathise at the end.
Malvolio's name suggests that he is a person of ill will and his getting a comeuppance certainly seems well deserved. Shakespeare however does write the punishment of Malvolio in such a way that he becomes so pathetic we can't at some point help feeling sorry for him. That, perhaps, is an illustration of Shakespeare's genius.