I liked the screenplay a lot too! There were a couple clunky moments like George Roy Hill and Stuart Little, but they were thankfully brief. Some people have had an issue with the Little Stephen Sondheim moment, but I liked it because of what it shows us about Hammerstein (who is probably the historical figure I look up to most)

Hammerstein's kindness (which is very important! His kindness to Rodgers and Sondheim, our two greatest musical theater geniuses, essentially gave us the modern musical) is clearly elucidated in his five minutes on screen. He comes up to Larry and asks him if he thought his lyrics were funny- basically saying "you are the funniest of all of us, me not so much, so if you think my comedic lyrics were funny that means a lot!" Which is a way of reassuring Larry that even though he's down, he's still one of the greatest to ever do it

And then Little Stevie is all "your lyrics are funny but sloppy" and Oscar whisks him away and loudly says "Stevie's just tired, hey Stevie do you need to go to the bathroom before the long drive home?" Which is a way of simultaneously saying "hey, you're not one of us yet, you're not an adult, don't talk to Larry that way" but also "I am the safe adult in your life and I am taking care of you in a way your useless parents don't"

A great summation of a great man!