Here is where we venture deep into hypothetical territory, as Bob Dylan would never in a million years make an album with The Roots. But let's imagine he did! Dylan may be rock's poet laureate, but he's a famously uneven live performer. Perhaps being backed by the most dependable unit hip-hop has would reinvigorate the fire in his belly to a state of consistency.
Dylan's gravelly voice couldn't be relegated to mere hook duty, so he'd be trading verses with Black Thought, whose slight rasp would serve as a proper foil. Considering that he'd be going toe-to-toe with a Presidential Medal of Freedom winner, Black Thought would definitely put some elbow grease into his lyrics too.