Death penalty is stupid, giving the criminal a quick and easy way out. *
Let them suffer, and I mean suffer, for as long as possible. Turn the hardcore cases into a workforce at maximum efficiency. Sleep should be reduced to a minimum, physical labour to a maximum, and meals should give them just enough energy to continue living and working. If they have enough energy to smuggle drugs and shank each other they're just not being worked hard enough.
I would have loved to see e.g. Saddam and his ilk work themselves to the bones for those they wronged. By god, there's still enough broken shit down there to keep a generation of workers busy. And even if there isn't, there's enough sand to shovel around to keep anyone busy for as long as they live and then some. I'm sure they'd be perfect for sniffing out and disabling bombs and mines, too. Why waste perfectly good expendable slaves by hanging them?
Damn my German genes. Sneaks up on ya, it does.

*
Germanys health minister agrees.