you have to remember His story lived on fro nearly 300 years, with apostles and disciples being horribly tortured and killed for being a christian - who's going to do that for something they don't believe in?
and of course the gospels would have had to have all been copied out by hand - again who's going to do that for a fake?
you're right in one respect though, the council of nicea was brought about due to the question of Christ's pre-existence, again, something which is not there in scripture unless you mis-translate the originals into latin and really squint your eyes.
most christians today do not have the gospel, which is why christianity sounds quite mental to non-believers, unless you actually relate what is in scripture.
don't get me wrong, it's still supernatural, because we are talking about God here, but as i opened my response with, there are logical reasons why the witnesses must be telling the truth.
RE: Who was Jesus according to scripture?