I'm glad you as a psychiatric professional focused on the opening "imprint" scene.
a brief opening scene that some (especially those unfamiliar with OCD etiology) will use to blame it all on mom
Your point is well taken: this is passé pop psychology--(perhaps deliberately? since it's frequently said to be an intentional link with Citizen Kane). But while Obsessive-Compulsive Disorder is now known to be due to "faulty brain chemistry" (not itself a very scientific-sounding way to put it, but I grant that it's valid), isn't it also possible that an overprotective mother may create lasting insecurities and reclusiveness of feeling and behavior in an oversensitive son? (I saw such a pattern in my own father, whose mother wouldn't let him play with the neighbor kids because they were too 'rough' and too 'dirty,' and who was never relaxed with people and spent his latter years rarely going out -- though he hardly could have been said to have OCD.) I think people discussing the movie have muddled the complexities by concluding that all Hughes' pecularities are explained by saying he had OCD.

Aside from this issue, I nonetheless of course agree with you as many would that the screenplay of The Aviator isn't profound. (But can you give examples of biopics whose structure lends itself to a deep and subtle analysis of the person whose life is being presented?) I repeatedly used the word 'fun' to stress that -- its lightness and superficiality make it frothy and enjoyable -- and also to contrast the film with Scorsese's other frequently un-fun films -- perhaps one reason for your finding it hard to see the special Mark of Marty in this one. It has the grandeur of mise-en-scène of Gangs of New York in it, but unlike that, isn't a disaster but a success.