There’s nothing more important than a solid story.   The problem for writers  is how to translate what Bob McKee/Blake Snyder/Linda Seger/etc. tells us into what each of us wants to specifically say.   In other words, how do you turn their theory into your story?   This is the crucial process of getting the story straight. 

The best thing that can happen during the writing is for the script to take on a life of its own.   That means you’ve tapped into something powerful.  It can also mean that what you set out to do and what you did are not the same thing.  An objective eye is essential to refine the vitality of the rough draft into the polished final.