You've not given me any reason that it "should have found evidence". I've asked you how much documentary evidence the average itinerant preacher left behind. Even ones that were relatively well-known at their time. How can you say that Jesus should have left documentary evidence, when you don't know if other itinerant preachers left "documentary evidence"?
If the historical Jesus was an "average itinerant preacher" then he isn't the Biblical Jesus in any meaningful sense. The widely-believed story is that Jesus was notable and politically significant in his own lifetime, founded Christianity in his own lifetime in the form of a number of followers who knew him personally and knew he was real, and that modern Christianity is a linear descendant of that original group.
There's simply no evidence of any such person or any such group of personal followers. That seems to me far more consistent with Jesus being made up out of whole cloth after his purported life and death.
You're disregarding everything I say. I'm not saying anything is exceptional in the Jesus story.
In my terms you are saying that. You have said twice now that you find the Jesus story plausible because it has elements that you think would make it exceptional amongst made-up stories of miracle-working messiahs. My point is that you could use the exact same argument for any such story just by picking out the story elements which are unique to whichever story you wish to privilege.
As for the comparison with Batman, Robin Hood and so forth it seems to me that your division of story elements into "meaningful"/"core"/"crucial" and not-meaningful/core/crucial is post hoc. To the Christians of, say, 80AD it might well have been that Jesus being crucified and being from Nazareth were just as much a part of his story as murdered parents and a bat suit are to Batman. My recollection was that crucifixion imagery was a regular motif in Christian thought by the second century at the latest, so it became an important part of the story very quickly.
I think a lot of Christians uncritically buy an implicit argument that goes like this: The Christ story got increasingly ridiculous over time, as demonstrated by the increasingly silly things in the later Gospels. Therefore if you draw a line back through the graph of ridiculousness over time you'll eventually get to the origin point which will be a real story with zero ridiculousness. The problem is that the origin point could equally well have been a fictional story with a low level of ridiculousness, and given the total lack of evidence from Jesus' time that he or his followers existed that seems more likely to me.
If the historical Jesus was an "average itinerant preacher" then he isn't the Biblical Jesus in any meaningful sense.
If there was a real guy called Jesus of Nazareth around the early 1st century, who was crucified during Pontius Pilate, and his disciples and followers that formed the core of the religious movement later called Christianity, to argue that Jesus was nonetheless "completely fictional" becomes a mere twisting of words that miscommunicates its intent.
At this point no matter how much evidence appear for a historical Jesus,...
To break up the awkward silence at the start of a recent Overcoming Bias meetup, I asked everyone present to tell their rationalist origin story - a key event or fact that played a role in their first beginning to aspire to rationality. This worked surprisingly well (and I would recommend it for future meetups).
I think I've already told enough of my own origin story on Overcoming Bias: how I was digging in my parents' yard as a kid and found a tarnished silver amulet inscribed with Bayes's Theorem, and how I wore it to bed that night and dreamed of a woman in white, holding an ancient leather-bound book called Judgment Under Uncertainty: Heuristics and Biases (eds. D. Kahneman, P. Slovic, and A. Tversky, 1982)... but there's no need to go into that again.
So, seriously... how did you originally go down that road?
Added: For some odd reason, many of the commenters here seem to have had a single experience in common - namely, at some point, encountering Overcoming Bias... But I'm especially interested in what it takes to get the transition started - crossing the first divide. This would be very valuable knowledge if it can be generalized. If that did happen at OB, please try to specify what was the crucial "Aha!" insight (down to the specific post if possible).