Somewhere, hyperprodigious Ryan Adams is whipping himself for being a laggard, because Gill beat him to doing a four-CD set of all-new material. Wretched excess? Not at all: These Days might be better thought of as four distinct, tight, hugely fun albums — in four fairly discrete styles — that Gill charitably bundles together. His high, not-so-lonesome tenor doesn’t grow tiresome even if you take in his trad-country, R&B/rock, pop, and bluegrass sets all in one sitting. But yes, we are praying it doesn’t give Rascal Flatts any big ideas.