I have greatly enjoyed Fr. Hunwicke's latest series -- beginning here -- for I mostly share his tastes and prejudices. After all, it is only natural that the court will demand that one's legal brief be complete and well-formed. Else ...
Beginning from a subsidiary point -- that a eucharist may be "incoherent" but still valid, this latter concept not admitting of degrees -- I inquire as to what is wrong (if anything) with the 1928 Book of Common Prayer service. (In this, of course, I claim no superiority for it, simply familiarity.)
Polemicists typically contrast some version of Cranmer with the traditional Roman canon. But simply restricting our attention to text, to form (order) and content, where is the problem? In the following, the Apostolic Tradition is used not because it is original, superior or anything other than the fact that, in its simplicity, it suggests four or five basic elemental structures.
No matter where one rests the "validity," if these are the typical elements, what is it that should (or must) be there that is taken to be missing? Is the actual problem with the additions (in blue) that are believed to suggest some antithetical doctrine? (Note: I didn't mark the unworthiness-language, which some may falsely suspect to be creeping Protestantism: it is, in fact, a big part of the Sarum rite.)