The request made by the ghost for Hamlet to kill his uncle seems a bit overboard to me, and a less radical request would be more appropriate. A more valid offer would be if the ghost wanted to help Hamlet prove to everyone how King Hamlet was killed by Claudius and let Claudius suffer the consequences of murder. If Hamlet would attempt to prove how his father died, then Claudius would eventually be put to death. By killing Claudius, Hamlet is making himself out to be the bad guy, and unless he can pull off the crazy act he will probably be killed also. The murder of King Claudius would seem to everyone as just an act of viol