I never said that a person is a criminal for breaking God's commandments. I don't believe that anything that doesn't have a victim should be a crime even if a lot of those actions are sinful, according to my beliefs. I was only saying that the death penalty kills the chance of their salvation (unless they get saved before execution). Like I said, I've seen murderers become truly saved after entering prison. Secondly, there are plenty of people out there who, if they were victimized, would care about their aggressor's salvation. If my whole family was raped, then murdered, I would still care about the aggressor's salvation enough to not warrant the death penalty because this person could still change, even if they had no chance of ever getting out of prison. No matter the circumstances, I would always still care enough about a person's salvation to not give them the death penalty. I'm sure plenty of others feel the same way. To me, the means justify the ends, for that is God's way.
Aside from theological arguments that many nonbelievers dismiss, I do agree with some of your points. Today's society has created a lot of misconvictions, and that alone is killing a lot of innocent people, and that alone could warrant the dismissal of the death penalty. On top of this, the cost of carrying out the death penalty is too high. However, your proposed position on punishment is too harsh. These people cannot get better in situations like that. I'm not saying to make it like Peewee's playhouse, but to your extent is not helpful or just.