I disagree with Vinzent's reading of Papias and Tertullian. Vinzent reads passages such as the following from Tertullian and takes them at face value:
Of the apostles, therefore, John and Matthew first instil faith into us; while of apostolic men, Luke and Mark renew it afterwards. These all start with the same principles of the faith, so far as relates to the one only God the Creator and His Christ, how that He was born of the Virgin, and came to fulfil the law and the prophets. Never mind if there does occur some variation in the order of their narratives, provided that there be agreement in the essential matter of the faith, in which there is disagreement with Marcion. Marcion, on the other hand, you must know, ascribes no author to his Gospel, as if it could not be allowed him to affix a title to that from which it was no crime (in his eyes) to subvert the very body. And here I might now make a stand, and contend that a work ought not to be recognised, which holds not its head erect, which exhibits no consistency, which gives no promise of credibility from the fullness of its title and the just profession of its author. But we prefer to join issue on every point; nor shall we leave unnoticed what may fairly be understood to be on our side. Now, of the authors whom we possess, Marcion seems to have singled out Luke for his mutilating process. Luke, however, was not an apostle, but only an apostolic man; not a master, but a disciple, and so inferior to a master — at least as far subsequent to him as the apostle whom he followed (and that, no doubt, was Paul ) was subsequent to the others; so that, had Marcion even published his Gospel in the name of St. Paul himself, the single authority of the document, destitute of all support from preceding authorities, would not be a sufficient basis for our faith.
Well, but Marcion, finding the Epistle of Paul to the Galatians (wherein he rebukes even apostles ) for not walking uprightly according to the truth of the gospel, as well as accuses certain false apostles of perverting the gospel of Christ), labours very hard to destroy the character of those Gospels which are published as genuine and under the name of apostles, in order, forsooth, to secure for his own Gospel the credit which he takes away from them. ... When Marcion complains that apostles are suspected (for their prevarication and dissimulation) of having even depraved the gospel, he thereby accuses Christ, by accusing those whom Christ chose.
Here Tertullian is doing what he does elsewhere, he is ASSUMING that Marcion had knowledge of the Gospels that he (Tertullian) uses. He assumes that when Marcion talked about "correcting the gospel of the apostles" that he is talking about written Gospels, when in fact Marcion was talking about gospel teachings.
So in fact, Marcion never made any comments about the canonical Gospels. But Vinzent sees this as evidence that Marcion knew the canonical Gospels or at least proto-canonical versions of them, by the names we now know them by. But that's not the case. Vinzent then ties to make a case that two things happened simultaneous: That Marcion was writing his Antithesis, which got leaked to the public, then in reaction to Marcion's Antithesis the Gospels of John and Matthew were produced, which Marcion then learned about and wrote about in his final draft of Antithesis. That's craziness.
Vinzent ends up relying on claims that Marcion's works were first published in draft form (possibly against his will). The canonical Gospels were derived from Marcion's draft Gospel, and then Marcion later published his final draft after the creation of the canonical Gospels. This makes what Tertullian wrote about the canonical Gospels coming before Marcion's correct.
Why Vinzent feels the need to concoct some scenario that makes Tertullian correct I have no idea. Quite plainly, Tertullian simply didn't know what he was talking about. Tertullian was simply wrong. There is no need to contrive a circumstance to make both Tertullian and Marconi correct in what they said. BeDuhn provides the much simpler explanation, when he notes simply that Marcion wasn't talking about correcting a written Gospel, he was talking about correcting gospel teachings.
Having said all that. I agree that there were most likely several versions of these Gospels and that all we have of Mark and John are versions that were revised for the orthodox NT. But I find it doubtful that Papias wrote the Prologue of John. I'm skeptical that we even know anything reliable about Papias or that the statements attributed to him are even authentic or correctly framed. All we have a fragments after all, quoted by others.
It seems to me that the core of John is a fundamentally Gnostic work. To me the question is: Was this a Gnostic Gospel that was revised to be less so, or was this a Gospel that represents a version of Gnosticism that was simply more orthodox in nature, and thus the Gospel didn't require much revision in order to be acceptable for the NT. For example if the Gospel was Appellean in nature, and thus supported the view that Jesus had a material body, maybe it was included simply for that reason.
But, elements of the text clearly contradict other parts of the text. This has lead scholars such as Teeple to conclude the work was comprised of layers that were not fully redacted and harmonized. This may be true, but if John 8 is so clearly Gnostic as it is, and puts forward the claim quite boldly that Jesus is the son of the Father that the Jews don't know, while the Jews are sons of the "Father of the Devil", then it would seem that this claim must, at some point, have been in harmony with the rest of the Gospel.
John to me hardly seems like a reaction against Marcionism, as Vinzent claims. It agrees with Marcionism far more than any of the other Gospels. On top of that, we have testimony from Origen that other Gnostics claimed to have an alterative reading of the Prologue which supported their Gnostic view. Right now the Prologue as we have it is quite odd, in that it is semi-Gnostic. It presents us with a preexistent Jesus who descends into the world from heaven, BUT who was also the Creator of the world. According to what Origen states, Heracleon (and perhaps the Valentinians more broadly) had a version of the text that said Jesus was NOT the Creator.
Now it also happens that the reconstruction of John by Teeple, in which he attempts to separate out which parts were written by different people, lends support to this. Teeple's work is based almost entirely on literary style. Within the Prologue Teeple identified three primary sources: An underlying Jewish poem, a Gnostic hymn, and an editor. Teeple proposed that the Gnostic Hymn was developed on top of an existing Jewish poem, and that this hymn was then integrated into the Gospel by an editor. It happens that several of the parts that he assigns to the editor are parts that provide problems for a more Gnostic reading.
For example, Teeple gives the following translation and assessment of John 1:12-14:
Gnostic Hymn:
John 1:12 But as many as received him, he gave to them authority to become children of God,
Editor:
to those believing in his name,
Gnostic Hymn:
13 who were begotten, not from bloods nor from the will of the flesh nor from the will of man, but from God.
If we recognize 12b as an insertion which may not have been in the Valentinian version of the Gospel, then we can see how the Prologue would actually fit with John 8:44. Because John 8 endorses the idea of predestination, i.e. that the Jews were born of the wrong Father, and thus they would not be saved. But 1:12b reverses this. With 1:12b how you were born doesn't matter, because you can "believe in his name" and thus be saved.
So with 1:12b in the Prologue, the Prologue is in disagreement with John 8, but simply by removing that part, the two are in agreement, or at least that portion of the Prologue becomes in agreement.
But now, if we accept 12b as an editorial revision and instead recognize the passage without it as the original, then the orthodox reading of the beginning of the Prologue now looks to be in disagreement with this part of the Prologue. If the Word created the world, then why is he against those who are from the world? That makes no sense.
Orthodox John 1:3 states: "Through him all things were made; without him nothing was made that has been made."
Heracleon said that in his version it says the Word did NOT make the world. But even in the orthodox version, if the Word made the world, then why do we read John 1:13? "children born not of natural descent, nor of human decision or a husband’s will, but born of God."
If the Word made the world, then why is being "of natural descent" a bad thing? Being "of natural descent" can only be a bad thing if the world is made by the demiurge, NOT by God nor by the Word. This reading complies with John 8.
So that's why to me the idea that Papias wrote the Prologue makes no sense. I think instead that Heracleon's version of the text was original, and the orthodox version is a Catholicizing revision. Or at least, I think there are reasons to consider this possibility.