I think the basic problem here is the way Watchtower theology construes the expression "died" at Ro 6:7. In this view, Paul is making reference to the literal, fleshly death that persons experience at the termination of life. Such a death wipes away the stain of sin, and like a prisoner who has done his time and paid his dues, he no longer has to account for those sins, despite the fact that he has not repented of them. Simply the physical act of death is enough to absolve him, or "acquit" him as the NW "T" has it.
In this view, a person who dies in sin, need have no further worries about its application, because when he is resurrected, his life is wiped clean and he is raised to life, to sin anew. Thus a person who, in the Watchtower sense has been resurrected into the post Armageddon world must now be judged on what he does with his future, and the new sins he commits. I believe this view to be wrong because:
1. Death does not wipe away the effect of sin. Only the blood of Christ does this. While in this life one needs to accept this provision by a conscious decision, else he will "die in his sin" and its effects remain for all time.
2. What sort of "death" is Paul talking about?. In this brief section Paul twice refers to "having died". In verse 2 Paul talks about us who are "dead to sin", and in verse 8, he speaks of us who "died with Christ", and both, like verse 7, in the past tense. The "death" that Paul is referring to, then, is something in our past, while we are still alive in the present.
Humanity, according to Paul has one of two options:
In the present we can be alive to sin, but dead to God. Or
We can be dead to sin, and alive to God. Which is his preferred option.
The word "acquitted" used here by the Watchtower translator[s], is interesting. As mentioned above the word is closely allied to the concept of "justification" or "declaring righteous", but most translators feel that that the analogy of slavery is pertinent. A slave owner had authority over a slave only while the latter was alive. But once that slave was dead, the owner no longer exercised any authority over him.
Paul's analogy seems to be that once we are dead to sin, while we are physically alive, sin has no authority over us. Like a corpse is incapable of reacting to physical stimuli, so those who are dead to sin, remain [or at least struggle to remain] immune to its blandishments.
NEB: "He is no longer answerable to sin"
NJB "He has finished with sin"
TEV: "Free from the power of sin"