Both The Voice and American Idol swapped out some members of the judges’ panels this season, and the results couldn’t be more different. On Idol, Mariah Carey and Nicki Minaj don’t even speak to one another, except in the language of silent disapproving eyerolls. Meanwhile, on The Voice, the judges all make fun of one another, but good-naturedly: Usher gets gently ridiculed for his sexy seated posture, Shakira lobs insults at all her male cohorts, and everyone despairs at how n