Problem here is not that one who insults the holy Prophet (PBUH) should be punished and / or what the sentence should be? Before one decides what is to be done with the Blasphemer, it has to be conclusively proven that he is actually guilty. To avoid an innocent being punished on mere allegation or hearsay; some kind of court system, be it a council of elders like Jirga or Panchayat, has been in existence since pre-historic times.
Undoubtedly anyone who insults our holy Prophet (PBUH) should be punished and even killed if so sentenced by the Court, but shouldn’t a Momin ensure that the person he was killing was actually guilty of the crime?
Asia Bibi’s case is still pending because she has appealed to Supreme Court that she never intended to insult the holy Prophet (PBUH). Supreme Court, on the other hand, decreed that calling Blasphemy Law a Black Law does not imply that Prophet (PBUH) has been insulted. Had Salman Taseer had been charged, tried and let-off, one could understand that being a zealot Qadri thought justice had not been served and therefore shot him. This however did not happen.
The mind-set that makes lawyers, judges and otherwise intelligent men make a hero of a cold blooded assassin and members of this forum boldly claiming that a Momin would do it a zillion times is frightening.