Like everyone, I'm prone to enthuse how utterly electric the jiggling phenomenon known as Beyoncé is. Yet the honeymoon's expiring, and those first doubts are creeping in. She is mutating into Mariah Carey, or, worse, Tina Turner. She does one magic single, then we turn a blind eye to three rubbish ones. She has the cold eyes of a mugger. She has another film out, and is tapping into the profitable gospel market.