I've seen so many testimonies from people who went to see Dylan live and say what amounted to, "All he did was come out on stage and croak a few incomprehensible things and then left. We were so disappointed."
What were they expecting?
Dylan is really inconsistent. I think Highway 51 Revisited and Bringing It All Back Home, Blood on Tracks, Blonde on Blonde, and a few others are immortal classics, but a lot of his output is pretty non-memorable. That isn't necessarily bad. Not even all of Shakespeare is great.
But as a performer he's generally terrible with occasional moments of brilliance.
He has a terrible, reedy voice and sounds like he's singing entirely through his nose most of the time. This is why so many songs he wrote are a lot better performed by pretty much anyone who isn't Dylan.
To pick another singer-songwriter from the same era, I'd say Joni Mitchell is either Dylan's equal or superior by almost any musical metric. Her lyrics are consistently top-notch, with emotional resonance instead of intellectual wankery, she gave room to other musicians to be their absolute best (like Jaco Pastorius or Herbie Hancock or Pat Metheny or Charles FUCKING Mingus), and that's without her actual genius as a performer.
She used her voice like a violinist used a Stradivarius. She could sing the phone book and move a grown man to tears.
Either way, Joni Mitchell >= Bob Dylan by every objective metric.
Don't get me wrong, Dylan is a genius songwriter (except when he isn't), but Mitchell is easily as good (and more consistent) and better at everything else.
