Is revenge emphasized more in Hamlet or in Macbeth?
Certainly revenge is much more a part of Hamlet's story than Macbeth's. In Macbeth, the Weird Sisters meddle with Macbeth out of malice, not because they are seeking revenge on him for some prior slight. Further, though Macduff does want to avenge his family after Macbeth has them slaughtered, his desire to depose and punish the tyrant existed long before Macbeth ordered their brutal murders. Likewise, Malcolm seeks to do what is best for Scotland and that is to dethrone Macbeth; it has less to do with revenge and more to do with what is right for the country.
In Hamlet, however, the plot doesn't begin to advance until Hamlet meets with his father's ghost and the ghost charges him to avenge his murder. Old King Hamlet instructs Hamlet to exact revenge on Claudius, and it is Hamlet's action (or inaction, as the case may be) toward this end that moves the plot along. Moreover, the motif of avenging sons runs through the play: first, young Fortinbras wants to attack Denmark to avenge his father's death and the loss of their lands; second, Hamlet has an actor recount the tale of Pyrrhus, son of the slain Achilles, when Pyrrhus avenges his father's death by slaying his killer; third, Laertes returns from France when he has learned of his father, Polonius's, death because he suspects foul play. When he learns that it was Hamlet who killed his father, it is Laertes's attempt to exact revenge that directly and immediately leads to the deaths of himself, Hamlet, Claudius, and Gertrude. Thus, revenge is a much more prevalent theme in Hamlet than it is in Macbeth.