The worst family dramas feature a one-dimensional "evil" mother or "cruel" father. Real complex families are filled with people who believe they are doing the right thing. The controlling mother thinks she is protecting. The cheating husband thinks he is surviving a dead marriage. When you can write a scene where the antagonist explains their actions rationally, you have real conflict.
What separates a simple argument from a generational saga? Complexity. A great family storyline operates on three distinct levels simultaneously: the surface conflict (what they are fighting about), the historical wound (what they are actually fighting about), and the systemic flaw (how the family is broken as a unit). The worst family dramas feature a one-dimensional "evil"
Unlike a thriller, a family drama often resists a tidy ending. People do not fundamentally change in two hours. Here are three nuanced resolution styles: The cheating husband thinks he is surviving a dead marriage
Stasis is the enemy of drama. Families in equilibrium are boring. Therefore, a catalyst is required. Often, this is a returning family member. This could be the "failure" who moves back into the basement, the aunt who was cut off for marrying the wrong person, or the half-sibling nobody knew existed. Complexity
This return forces every member to confront their own choices. If the black sheep can come home, why can't you leave? If the exile is forgiven, why are you still being punished for that mistake in high school?
Not necessarily a literal ghost, but the absent parent or deceased sibling whose memory poisons the present. In This Is Us, the ghost of Jack Pearson hangs over every decision his children make. The Ghost is a perfect character because they cannot defend themselves or change. Living relatives project their best and worst traits onto the void.