I think Dylan had a great "sprechstimme" voice as they say in Germany -- the Lotte Lenya/Brecht voice -- but, as Rick says people do, I think it was at its best in the slightly later albums -- "Ballad of a Thin Man" era, and all of "Blonde on Blonde" -- the pre-accident voice. Has anyone ever sung/coughed "cough" better than he does on "Visions of Johanna"? Those albums are full of little vocal details like that -- I can't comment on his guitar playing.
yours, Peter T.