Motivation must be strong and compelling. Taking a scene a beat too far detracts from the impact. You'd be surprised how many stories take inexplicable detours along the way. No one is perfect. Characters that merely react to external forces are boring.
Dialogue is very much part of characterization.
The audience should never recognize they are being fed facts. Dialogue should be kept to a minimum. The story should be told through action. Oh yes, your writing ability will be judge . That's true, but reading it is not the same as implementing what you have learned, or recognizing when you have missed the mark.