I had a magnificent opportunity to hear Gwendolyn Brooks speak and recite her poetry in Charlotte, NC before she passed away. Brooks has an amazing body of work that tends to create, as your question suggest, a picture of black urban life. Much of her poetry concerns life in Chicago, as that is where she worked with the Black Arts Movement.
While many poets of her time were blaming the cities for the problems of the black members, particularly young black men, Brooks places some responsibility on the individuals themselves. If you look at the poem "We Real Cool", Brooks examines the attitude of street youth, but provides an ending "we die soon" that shows the fatal outcome of living their lifestyle.
Yet, some others of Brooks's characters do seem small and unimportant in their cities, still they make the best of what they have. Examples of this include the poems "Of Dewitt Williams on his way to Lincoln Cemetary" and the "Sundays of Satin Legs Smith". In these poems, the individuals are relatively ordinary, even insificant to others, but have a small level of interest inherent within themselves. One critic describes this as:
Brooks is content to describe a moment in the lives of very ordinary people whose only goal is to exist from day to day and perhaps have a nice funeral when they die.
Finally, Brooks give insight into characters who experience realizations about their own responsibility in some of the tragedies of urban black culture. In "A Boy Died in My Alley," the speaker receives notice that a boy was murdered in her alley. At first she attempts to blame it on a failed society or system, but ultimately realizes that since she knew the boy too, she was partially responsible because of her failure to act. This is expressed in the line:
And I have killed him ever.