One of the things which should be done is to seperate "Jesus Christ" and "Jesus of Nazareth." "Jesus Christ" is the Christian godhead figure, the Son of God, and includes the Greek "Christ" or "Anointed One." Jesus of Nazareth (call him "JN" to differeniate him from "JC") is the historical personage, JC is what the early Christian church made JN into.

If you accept that there was a JN person, perhaps a sage or rabbi, living about 2K years ago, then a case can be made that what we call "the New Testament" is at least partially from from what he taught. If you want to argue that JN is JC, then you move into a different realm entirely.