Dylan was a bad singer
But an excellent songwriter
I really like Dylan's singing voice as well, through probably "Time Out Of Mind." Unfortunately, his voice really seemed to really go downhill after that. I've always thought "Dignity" was one of the most underrated songs of the 1990s...his voice still sounded OK on that.
I haven't seen the movie yet (I know Bob Dylan's history pretty well, but I'd like to watch this one day). You're definitely right about him being a fantastic songwriter (probably the most influential songwriter of all time). He's a very underrated guitar player also...I really love his acoustic playing a lot.