The miracle of changing water in wine is anti-marcionite. Dionysos doesn't matter nothing here.
So Couchoud:
It is more certain that he wished to refute Marcion and his trenchant aphorism that new wine should be poured into old wineskins. Though he may be conscious of the newness of Christian doctrine, yet he does not wish to reject utterly the whole of Judaism. Jesus therefore miraculously draws the new wine out of the old pots of the Jews.
(Creation of Christ, p. 247)
If the consensus is already that John is a Gnostic Gospel later catholicized (see for example the view of April DeConick about it) then for the same reason the Parable of Wineskins is Gnostic and marcionite in essentia, given the fact that it is confuted even by the Catholic editor of John.
Nihil enim in speciem fallacius est quam prava religio. -Liv. xxxix. 16.
2 On the third day there was a wedding in Cana of Galilee, and the mother of Jesus was there; 2 and both Jesus and His disciples were invited to the wedding. 3 When the wine ran out, the mother of Jesus *said to Him, “They have no wine.” 4 And Jesus *said to her, “Woman, what does that have to do with us? My hour has not yet come.” 5 His mother *said to the servants, “Whatever He says to you, do it.” 6 Now there were six stone waterpots set there for the Jewish custom of purification, containing twenty or thirty gallons each. 7 Jesus *said to them, “Fill the waterpots with water.” So they filled them up to the brim. 8 And He *said to them, “Draw some out now and take it to the headwaiter.” So they took it to him. 9 When the headwaiter tasted the water which had become wine, and did not know where it came from (but the servants who had drawn the water knew), the headwaiter *called the bridegroom, 10 and *said to him, “Every man serves the good wine first, and when the people have drunk freely, then he serves the poorer wine; but you have kept the good wine until now.” 11 This beginning of His signs Jesus did in Cana of Galilee, and manifested His glory, and His disciples believed in Him.
36 And he spake also a parable unto them;
No man putteth a piece of a new garment upon an old garment;
otherwise both the new maketh a rent,
and the piece that was taken out of the new agreeth not with the old.
37 And no man putteth new wine into old wineskins;
else the new wine will burst the skins, and itself will be spilled,
and the skins will perish.
38 But new wine must be put into new wine-skins;
and both are preserved.
The headwaiter (symbol of Jews and Judaizers) didn't realize the miracle of Jesus since he thought that the pots did contain only and always wine until that time. Therefore John 2:1-11 may be still the product of the gnostic proto-John (and not part of the his catholic alteration), insofar the ''new wine'' (the knowledge of the Son of an Alien God) was inserted only in that very recent time. At any case, it is evident that John doesn't like the drastic marcionite dualism between old and new and attempted to mitigate it.
Nihil enim in speciem fallacius est quam prava religio. -Liv. xxxix. 16.
