I recently had a reading of a play I've been writing for more than a decade in front of a dozen or more playwrights (led by Sarah Gubbins, FAIR USE and many other plays). The opportunity presented itself at Chicago Dramatists, with which I'm pleased to be associated as a Network Playwright.
I got very useful feedback, but the main take-away was the power of the deadline. I had learned less than a week before the reading that I'd get this opportunity and had to distill hundreds of pages of notes and a couple hundred more pages of dialogue and stage directions into a comprehensible first-draft, bona fide script.
Never underestimate the power of a deadline. For better or worse.