Pacino's characters are always warm, intimate and personal - yes even Michael Corleone - and in this film also sensitive and kind. Here he gets to share those qualities with lucky children whose parents abandon them.
As a father, he's tough when he needs to be, tender and concerned when he's called on to be and just a big kid when he feels impelled and its appropriate. His character here, as in many of his roles is self-centered if not self-obsessed, and that can drive the adults around him bonkers when they need his attention, but he never lets the children down.
His house evolves into a kind of wayward home - a place to where his ex-wives's children return of their own will because it's the only place they feel wanted comfortable and respected. There they matter as human beings.
Pacino is a playwright and apparently a good one, but he seems less concerned with the art of his craft and more concerned with it being lucrative for the benefit of his now extended family. He's shown to be the only responsible adult in the movie and he's barely hanging on to the coat tails of sanity as it is. The children all seem to have more sense than the adults. With Pacino, they take an us against the world approach to their problems. We root for them, of course, because they're much too important to be ignored and they've got the spunk to insist that they be seen and heard.
The household has a summer camp bunk mate feel. The children have distinct and in some way opposing personalities. Each stands out as special and for the most part there is little conflict. That may be a contrivance or it could be a believable happy accident.
Tuesday Weld, Pacino's estranged wife and the mother (with different fathers) of four of the five children, is the embodiment of the enemy. A selfish, uncaring, unloving mother - oh, they're out there - but she probably also represents society on some level especially at the tail end of the me-decade 70's. Perhaps for the sake of ratings there is no direct reference to drugs or promiscuity, but it ain't a far leap to make to explain the history of the characters.
As at least one other reviewer has said, the film probably works a lot better for people who have lived the kind of life portrayed.
