The wording in the Josephan TF - He won over many Jews and many of the Greeks. has been viewed as problematic as the gospel story has little to back up this idea. The focus of the gospel Jesus figure is that of a Jewish messiah figure - fulfilling OT prophecy. The NT story waits for Paul to do the Gentile outreach. However, early christian history identifies Marcion as someone with other ideas - his non-Jewish Christ figure was a Christ figure for everyman. Two stories, Jewish Jesus and the Pauline and Marcion non-Jewish Christ figure. Two stories that were fighting for dominance in the early christian church. Rather than seeking to accommodate both ideas, Marcion was branded a heretic and by all accounts excommunicated by the early church.
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Years prior to Eusebius someone had a motive in linking Greeks/Gentiles to the ministry of the gospel Jesus - Marcion.
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It is, however, well that Marcion's god does claim to be the enlightener of the nations, that so he might have the better reason for coming down from heaven; only, if it must needs be, he should rather have made Pontus his place of descent than Galilee. But since both the place and the work of illumination according to the prophecy are compatible with Christ, we begin to discern that He is the subject of the prophecy, which shows that at the very outset of His ministry, He came not to destroy the law and the prophets, but rather to fulfil them; for Marcion has erased the passage as an interpolation.
Tertullian. Against Marcion . Kindle Edition.
Thus, for Marcion, from the beginning of Christ coming down to Capernaum - he was the non-Jewish Christ - the Christ of everyman. Yep, Pauline theology - but Marcion backdates the everyman's Christ to the very beginning of the decent to Capernaum.
(Basically, of course, indicating two Christ figures - the Jewish Messiah/Christ figure - plus the 'heavenly' Christ figure for everyman. The NT has a story to tell - first the Jewish messiah figure followed by the Pauline everyman Christ figure.......but human reality links body and spirit - which perhaps is what Marcion is attempting to articulate - and the church fathers were not having it....)
Anyway, what this idea regarding Marcion does do is suggest that a core TF could have been interpolated by Marcion - motive and opportunity - seemingly he went to Rome - were there. (along of course with the charge that he ''seems to have singled out Luke for his mutilating process.'' Tertullian. Against Marcion . Kindle Edition. )
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Marcion had the motive for an interpolation of 'many of the Greeks' into a core Josephan TF. On motive alone he has to be the prime suspect. Did he do it?