Wilco’s latest album Sky Blue Sky is one of the most subtle recordings in the group’s history, a surprise to some after the more overt experimentalism of Yankee Hotel Foxtrot and A Ghost Is Born, and even more of a surprise to those who expected a radicalized Wilco now that guitarist Nels Cline is on board. It would have been too predictable for Tweedy & Co. to have Cline lay...