Mark, I love your essay, although I have to point out one thing you didn't bring up: lyrical content. Part of Lennon's crit-cred was his love of wordplay (which sometimes devolved into word salad, as on "I Am the Walrus," but oh well); Paul's lyrics were often seen, fairly or no, as trite.
Sure, I'll give you that, but at the same time his repeated misogyny ("Run For Your Life", "Getting Better All The Time", et al) is just as big a strike
against his lyrical ability. Anyway, it was EXACTLY the compare/contrast of Lennon/McCartney as songwriters that made their whole oevre what it was. I think each of their solo careers shows compellingly that they truly missed each other's contributions.