Best cut: Allen Toussaint's "What Is Success," about the "so necessary" spiritual expenditures entered above a record company's bottom line. Whereupon Raitt pays her tribute to schlock four times over. Typically, she can uncover a stirring moment in the most stillborn possible-single, but the limits of her integrity have already been defined by three flexible, often playful, yet obviously uncompromising albums, and when the strings and woodwinds rise up, they dispossess her. Even "What Is Success" suffers a setback when Raitt accedes to Toussaint's impersonal "he." That's no "he," Bonnie--that's you. B