I’ve always thought of Jessye Norman as too American in her voice. Too grande, too loud and missing some subtlety (though perfect for Strauss!). After hearing this recording I noted the same in the voice of Barbara Hendricks. In reading about this album, I discovered it was also the critique at the time. Hendricks delivered a beautiful crossover album with the Labèque sisters, but she made it more a classical album than jazz. And as a classical voice, hers is perfect. It is just missing that jazzy feeling.
Maybe that was the point of this: to create a bridge between the two, by using a young (at the time) soprano and couple her with veteran Gershwin interpretors in a chamber music setting. André Previn did something similar six years later, with Kiri Te Kanawa, but he went overboard with the orchestral arrangements. In comparison, this is quite a good recording.