If Jesus Christ is not God, then what kind of fallacy is Romans 5:8?

Logical arguments are indeed part of the basis of belief in Christianity. Many believe the logical arguments based on scripture and that the testimony of the authors are claimed to be proof that Jesus Christ is God. It is the bottom line that these beliefs are assumptions based on anecdotal evidence, and vary among Christians. There is insufficient evidence to every conclude that these arguments amount to sound logical arguments that conclude Jesus Christ is God, because it is assumed Jesus Christ is God based on anecdotal evidence.

Jesus Christ is God/or was obviously has an interpretation that some people seem to miss. Let's assume Jesus existed as a physical person with a soul. Lets assume God exists, well as anything God wants to exist as. If Jesus Christ in the flesh simply did or said nothing but what God did through him because Jesus' will was to only do what the father has shown him to do, a person could say Jesus was God because Christ acted exactly as God, yet Jesus had a will of his own, therefore not being actually God. Jesus merely had one decision with his own will and that was to do nothing lest he saw his father do first.
So Christ represented God perfectly in words and behaviors but Jesus also waited to see what the father did first, making Jesus separate from God.
Jesus is God means Jesus showed us how God would be if he was a part of the world.

Logical fallacies are about logic and reason. Religious beliefs and the written things that outline these beliefs have nothing to do with logic and reason. That's not a criticism about religious beliefs. It's simply a logical statement. So, trying to apply logic to quite literally any sentence in any scripture in any of the 4,200 religions of the world is impossible. Example: "My religion says that every cloud holds a piece of baby Jesus." "Gandhi was Buddha and when he died, the sins of all Nepalese babies were removed." As Bo said, these are simply statements of faith. There's no logic or reason in them.

Like all scripture, the interpretation of the scripture depends on assumptions made form other references, tradition, and the doctrine and dogma of the religion and in some cases individual churches. In most traditional churches the assumption of belief is Jesus Christ is God, therefore particular verses will be interpreted as Jesus Christ is God. In logic this would 'Begging the Question, or often called a circular argument. Based on all the scripture some churches do not believe that Jesus Christ is God, therefore they do not interpret this verse to mean Jesus Christ is God.

Tugger's & Bo's points on this question are on the mark....IMOP, futile to further discuss, unless a radically new viewpoint is put forth.

This seems like a sound argument. It is not necessarily valid, as there are several facts it assumes that might not be true ("Christ is the son of God," "God exists and can love us").

These are simply statements of faith. I would not call a fallacy.

I would personally say that's a "begging the question" fallacy because you have to prove Christ really did have the supernatural powers necessary to save people from sin.