The problem with "Life without Parole" is the defendant can still have family visits, etc., albeit through a glass shield. A victim's family no longer has that luxury. Justice denied. If, for example, one could be sentenced to "Life without Parole and total Solitary confinement with no family or other visitors, then that might work.But I'm sure most defense lawyers would sue for that being "cruel & unusual" punishment.
Taking a life in this context (Capital Punishment) is a matter of justice, and nothing else. It's not "vengeance" at all. One only takes the life after the entire justice process has run its course and it's confirmed that the correct and appropriate punishment is Death. "Vengeance" involves taking that life without the benefit of the full justice process (ie, "lynching"). That is wrong and should never happen.
With forfeiture of the defendant's life, at least the VIctim's survivors and the defendant's survivors are now on equal footing. Horrible footing, yes, but "equal."