U is for unexpected
There's always been something new and unexpected from Dylan. The album Highway 61 Revisited gave the world the snare drum opening (Sringsteen described it as kicking open the door to your mind) of Like A Rolling Stone. It still ranks as number one in Rolling Stone's Top 500 Songs Of All Time. At six minutes, it seemed way too long in a world used to the two and a half minute pop song. But demand for it soared and it is a landmark work.
An organ tapestry from Al Kooper and blues guitar from Mike Bloomfield buttressed lyrics that were deep and spoke into philosophy. He left behind the image of the political folkie.
Also on the album was the epic Desolation Row, elaborately constructive lyrics - this is poetry, and it lead the way for the hippie poetry-to-music and artists like Simon and Garfunkel to follow.