How time flies. Five years ago the second-generation Cadillac CTS had just debuted at NAIAS. While prettier than the original, it was also fresh, exciting, and proof that Bob Lutz’s General Motors could turn out a damn fine car when it really wanted to. People who hadn’t owned a GM product for decades bought one, my father among them. Five auto shows on and we’ve glimpsed Cadillac’s future with the 2013 ATS. Does the 2012 CTS seem well beyond its sell-by date? Or does the old car, with a new 3.6-liter V6 engine and a new Touring Package, retain some compelling advantages?