The good and the bad in Fitzgerald's The Last Tycoon

As I continue reading F. Scott Fitzgerald's final (unfinished) novel, The Last Tycoon, I just keep wishing that - he'd been able to finish it! There's so much promising material, yet so much dreck as well, and given the thoroughness of his notes (included in the Scribner edition) and his commitment to rewriting and revising, we can be sure he would have improved this work, maybe not to the level of Gatsby but still, had he lived longer (he died of a heart attack in 1941, w/ the novel about half-completed). The good stuff remains the incredibly thoughtful and hilarious insights into the film industry, as seen through the eyes of the protagonist, Monroe Stahr - how he handles ingenues, washed-up actors, suicidal cameramen, investors, hack writers, over-sensitive directors, and so on - all w/ a keen sense that he has to create the aura that his decisions and reactions - and there are many - are always right, while secretly aware that sometimes he just has to make a decision, which may or may not be the right one, but the trust his underlings have - or the fear - makes them think he's always right. (Obviously, he usually is or he wouldn't rise to that level in the competitive industry.) What's bad? First of all the ridiculous narrator, the daughter of a rival film producer; we can see that FSF started out trying to create a female Carroway to tell this story, but he completely loses sight of her as he moves along and the later chapters are not anything she (or any other narrator except, possibly, a personal assistant to the producer) could have written. I think FSF could have mended that on a re-write. Second, thought the business story is powerful - who doesn't want more info on the inside workings of Hollywood in the studio ear? And we know FSF saw this from the inside - the love story that supposedly drives the narrative is DOA. Stahr supposedly falls for a young British woman, Kathleen, whom he glimpses on the back lot one night, because she looks like his late wife; he obsesses over this woman, final gets her to agree to go for a ride w/ him, they go to his beach house under construction, they have sex - OK, but really what's driving him? In Gatsby, the TGG loved Daisy and lost her and builds his life around winning her back (she's also a trophy, showing that he's arrived and the height of socieety). In this novel, Kathleen means nothing to him, and we don't for that matter know anything about his late (or is it is ex?) wife, either. He just flips for this young woman and pursues her and wins her (she seems a little too proper to have sex w/ him on their first date, but so be it). FSF would have had to think through this relationship more if it's meant to carry a novel; not sure, at that point in his life, if he was able to think through the nuances of a complex love relationship. He really needs an insightful narrator to do the thinking - this narrator doesn't work, nor would 3rd-person omniscient.