What folks call a "great song" varies greatly from person to person, methinks.
For instance, I consider
THIS
a great song.
I know that many of you will probably not consider it such: its meaning is not totally clear; it doesn't tell a coherent story. However, I find the lyrical content to work the same way on my conscious as do dreams -- it does NOT mean anything concrete, but it evokes such strong emotional response from me that it's almost real. And I know that I am not the only one to feel this way.
So, some of you may -- objectively -- point to this as the type of song that is "passing" for great songwriting, but is still just crap.
But emotion is not objective.
This is brilliant songwriting, as good as just about anything that Dylan ever did.
But then, that is my opinion.