I can imagine that if followers of Theudas had survived and flourished after 70 CE and wrote things about him, their writings wouldn't say, "He was a normal guy and nothing out the ordinary ever happened," but instead would say things like how amazing he was and that his life and deeds were predicted by the OT.
Given what little we know about Theudas (but supplemented with what Josephus and other sources say about the Fourth Philosophy), I'm inclined to think that he was a Jewish man who agreed with "Pharisaic notions" (such as resurrection of the dead, as per Josephus) and rejected the oral Torah ("the customs of our fathers were altered ... by this system of philosophy, which we were before unacquainted withal") and believed in the Messiah ("that one from their country should become governor of the habitable earth") and thought of himself as being some kind of Joshua redivivus, and that he and some of his followers were consequently killed by the authorities.
Is this not similar to the story of Jesus in the NT? Jesus (or the literary figure called Jesus) is presented as being a Jewish man who agreed with "Pharisaic notions" (like resurrection of the dead) and rejected the oral Torah (“Why do your disciples not walk according to the tradition of the elders?") and believed in the Messiah and people were "unacquainted" with his "system of philosophy" (“What is this? A new teaching with authority!") and he thought of himself as being Daniel's "son of man" figure, and he and some of his followers were consequently killed by the authorities.
Jesus strikes me as being like the kind of Fourth Philosophers Josephus describes in War 2.13.4.
These were such men as deceived and deluded the people under pretense of divine inspiration, but were for procuring innovations and changes of the government; and these prevailed with the multitude to act like madmen, and went before them into the wilderness, as pretending that God would there show them the signals of liberty. But Felix thought this procedure was to be the beginning of a revolt; so he sent some horsemen and footmen both armed, who destroyed a great number of them.
Is this not similar to Jesus' activity in the NT? In Mk. 6:30-44, for example, Jesus takes his followers to a "desolate place" and "deceived and deluded the people under pretense of divine inspiration" and showed them the "signal" of multiplying bread and fish.
Meanwhile, the apostles gathered around Jesus and brought him news of all they had done and taught. And he said to them, “Come with me privately to a solitary place ..." So they went away in a boat by themselves to a solitary place ... And he began to teach them many things ... the disciples came to Jesus and said, “This is a desolate place ...."
And just like I'm more inclined to think that Theudas was a Jewish Fourth Philosopher instead of an imaginary figure that was turned into a human by Josephus' time or was an invention of Josephus, I'm inclined to think the same thing about Jesus, even if the same arguments are made about him that could be made for Theudas, like the issue of the lateness and trustworthiness of Josephus (who, like Eusebius, worked for the emperor).
All things considered, it seems simpler and makes more sense to me to suppose that Jesus was just another crazy Fourth Philosopher (whose life and deeds were embellished by his followers) than an imaginary figure that was turned into a human by Christians who didn't like Marcion.