One bit of conventional wisdom that I like is that an engaging script should be both familiar and different. Too much emphasis on familiarity (formula) and the story will seem pointless to the audience (“Been there…”). Too much “uniqueness” and the story will (for most viewers) seem too alien to follow or get involved with. The “standard” paradigms (there are many of them) provide the sense of familiarity. But a good story consists of many smaller, ad hoc (variable) structures that exist beneath or beyond the typical macro structures like Field’s 3 Acts, Truby’s 22 Steps, Vogler’s Hero’s Journey, etc.). If the micro structures are sufficiently enthralling for the audience, then a story can get away with bending / breaking the formula of any or all of the established macro paradigms. But it’s not a case of formula vs. freedom; it’s a matter of juggling the various kinds of structures in a way that keeps the audience involved and provides a sense of satisfaction at the end of the story.