These families are like caper or suicide mission teams. Each member of the family has a specialty. But the point of the crazy family members is not to form a single team but to co-exist as individuals within a single house.
These stories don’t set diversity against unity. They say that community only happens because of diversity.
It’s like an old Brueghel painting. In one corner of the painting people are ice skating. In another a blacksmith does his work. In another corner men return from a hunt.
Each character is caught up in his own activity, unaware of what others are doing. But we the audience can see all of them living at once. Each individual seems to be connected to the others, not by someone’s command, but by an invisible hand of spirit in which everyone quietly respects everyone else’s passion.
In the quirky family comedy, this “Brueghel effect” is created by using the “buzzing household” technique. A big old wooden house with lots of rooms is filled with members of an extended family each totally intent on his own activity. Oftentimes they aren’t particularly talented at what they are doing. But what’s important is that they are passionate and not afraid to stand out as individuals.
Typically this community of diverse members is set in opposition to an outside authority that wants to force the family to live like everyone else. Far from creating community, this outside authority is intent on destroying individuality and community.
The Royal Tenenbaums is a totally front-loaded movie. It sets up the crazy family members but doesn’t know what to do with them. All of their unique achievements are behind them. And none of their talents is used in the present tense story.
Also you can’t make characters looney and cartoonish and then try to get audience sympathy when they apparently feel real pain. Emotion can only come when the story has been set in some recognizably human world. And this family seems from another planet entirely.