When I reviewed Bon Iver’s “For Emma, Forever Ago” last year, I ended the piece by saying, “Whether [Justin Vernon] is heading out of his father’s cabin towards a long, significant career is hard to predict, and the perverse romantic in me almost wants him not to bother trying. “For Emma, Forever Ago” is such a hermetically sealed, complete and satisfying album, the prospect of a follow-up – of a life for Vernon beyond the wilderness, even - seems merely extraneous.