The writer can come through so strongly he might as well put his face on the screen and speak the words and move the puppets himself. And the rhythm of artificial paradigms can make the plot predictable, which spells death. Balance three elements in what I call honest writing. The characters must be free to make honest decisions and shape their lives in an honest way so the drama unfolds honestly. The writer can create any situation he feels a character might create and will force the character to react dramatically, but honestly.
Realism is a very different thing than honest writing.
The writer is a storyteller - his skill is in knowing how to tell a good story, but an honest one. How you shape your plot is your strategy for telling the story. I like to think of crafting a story and plot like an architect designs a house. Windows so they can see out. Doors so they can get in and out and block the weather.