Ajmal Kasab's hanging has given a sense of justice and relief for many Indians for his role in Mumbai 26/11 Terror Attacks, but the other masterminds of Mumbai terror attacks are still at large in Pakistan, be it ISI and other Terror organizations.
I strongly opine that homicide in return for homicide is barbaric as it resembles eye for an eye and tooth for tooth justice of medieval times and uncivilized. France and Germany have completely done away with death penalty and reported lesser crime rates. Many studys' conducted in US and some other countries where death penalty is still in force have proved that, it doesn';t have a deterrent effect on crime rate and more than death penalty, it's rigorous imprisonment for life that has more deterrent effect than death penalty. Incarceration for life proved to be more effective in preventing repetition of the same or other crimes by the same convicts than that of death penalty. In countries, where death penalty has been abolished less crime rates have been reported.
Apart from incarceration for life, solitary confinement and shaming the person through social boycott etc are other options. For crimes of rape and acid attacks also, incarceration for life and the above two suggested alternatives could be considered as viable alternatives to death penalty in addition to confiscating the entire property of the criminal and paying it as compensation to their victims. Educating the guilty regarding the barbaric and heinous nature of their crimes and making them feel ashamed for their crimes and their crimes' lethal and traumatic impact on the minds, limbs and lives of their victims through reformist approach and making them truly repentant for the heinous crimes