The "O" argument

[Dawid]

Likewise, the unification of the Peshitta tradition can be explained. It was used by only two communities, essentially isolated from outside influence. Because old versions are regularly burned or buried, we would eventually expect to naturally find no more variants, even where there were variants originally.

I believe in the "innocent until proven guilty" policy where this is concerned. In order to even consider the possibility whether the CoE did standardize the Aramaic NT mss, one first needs to find an example of them altering any of the readings in their mss collection, and there's nothing. It's the SOC who did alterations not the CoE, and western scholars often don't differenciate between the 2 textual traditions, either out of ignorance or convenience, always be aware of this. The fact is there are no grounds to accuse the CoE of standardizing or altering the Peshitta.

Yes, but in order to prove that there were never variants one needs to have seen a much broader range of ancient Peshitta mss.
And I never said "alter." That was your word. I also do not intend to suggest that the modern Peshitta is any kind of critical text. Rather, that it is possible that it was one out of several competing texts, and this one came out on top as the standard one. So I'm not really talking about standardization of the text so much as standardization of usage.
We would need evidence of other versions in order to prove it, you are correct. But in order to suggest it as an alternative to an equally unproven, and unprovable, explanation of the continuity of the Peshitta and (minor variants aside) Peshitto versions extant? I don't think we need evidence to suggest an alternative to a theory that also has no evidence other than the silence of the manuscript tradition.