A better death penalty?

Last night I saw episode four of season three of Babylon 5, a sci fi TV show from the early 1990s. This episode deals with the death penalty sort of. The show is set in the year 2260, so naturally there have been many advancements. One is a reform of the death penalty. In stead of killing someone convicted of a capital crime, the criminal's personality is "wiped" from his body and a new benign personality is substituted. The person is given a new identity and purpose, to serve society in some way. Also, the person is moved to a different part of the galaxy to prevent any revenge by those harmed by the person's crimes. The situation is described as "more humane" and the penalty is called "death of personality."

The episode is really well-written and well-acted, so rather than discussing how this plays out in the episode (which would require spoilers), I'd rather talk about this new version of the death penalty.

One reason for inflicting the death penalty is that the criminal is assumed to be beyond the point of being reformed. The person is a danger to society and also to himself or herself and the only way to prevent that danger is to remove the person from society. Classically, removal is achieved by death or by banishment. In our time, life imprisonment without parole also fulfills this function, assuming the prisoner does not escape. "Death of personality" also achieves this end by suppressing the criminal personality and substituting another state-imposed personality. The result is the same body with a "different person" inside. The unreformable criminal is thereby removed from society.

Regardless of whether this substitution could actually work, my question is, is it really more humane? There is no indication that the criminal feels pain or physically suffers in any way during the treatment. The memories, feelings, inclinations, attitudes and desires are gone. The criminal is for all intents and purposes in a vegetative state. The new personality is an artificial construct imposed by the state in order to receive some benefit from the continued life of the body. Maybe the state feels more humane for not having killed the body, but putting it to any use the state sees fit is contrary to the dignity of the person (even when the person is a criminal). I really don't see any difference between "death of personality" and using the bodies of the executed for whatever scientific or medical purposes one could imagine. It's even worse than that. It's a form of benign enslavement. Programming someone to want to do good is far different from them freely choosing to do good. The human is turned into a well programmed robot; the freedom of the person is no longer respected. It may feel more humane, but in actuality it is not.