I wasn't impressed with the play, either- and I am familiar with Raisin in the Sun. The first act, which does run most parallel to Raisin, is stronger than the second, whose sole purpose seems to be a vehicle for racial jokes and the moral, "everyone's racist"- which Avenue Q managed to do in one song.
The deaf character in the first act seems to exist solely to be the butt of jokes (although one is pretty funny), and Christina Kirk is giving one of the worst performances I have seen on Broadway in a while.
"...everyone finally shut up, and the audience could enjoy the beginning of the Anatevka Pogram in peace."