Once upon a time, being the “Cadillac of <insert a noun here>” meant something magical. The problem is: it’s been 60 years since Cadillac was “The Cadillac of cars.” While the phrase lingers inexplicably on, GM is continues to play off-again/on-again with a flagship vehicle for the brand. The latest example is the all-new XTS. Instead of being “the Cadillac of flagships,” the XTS is a place holder until a full-lux Caddy hits. Whenever that may be. In the mean time, Detroit needed to replace the aging STS and the ancient DTS with something, and so it was that the XTS was born of the Buick LaCrosse and Chevy Malibu.