Bob Dylan is, I think, the unavoidable answer here. As a writer of song lyrics he has extended the form farther, and written more interesting examples, than probably anyone else in rock. Chuck Berry was much better than most people give him credit for, because his guitar playing was so flashy and his music was so rhythmic. I heard "Too Much Monkey Business" on the radio recently, and really listened to the words -- talk about social commentary! Berry nailed most of what has happened to our society over the last fifty years in seven verses. Jesse Winchester, whom most people have never heard of, is very good. Pete Brown, who wrote some song lyrics for Cream, was very interesting. Lou Reed is a great lyricist.
Probably my favorite, however, is Ray Davies of The Kinks. He had an extraordinary range of interests, could convey an amazing range of emotions, combined humor, drama, and social commentary, and was just a painstaking craftsman when it came to the words of his songs.
Having said all this, I must add that the lyrics that work best by themselves often don't make the best rock songs. Rock gets its energy from the interplay between words, vocals, music and instruments. If the words tell the story all by themselves, then they leave no room for the other elements. As Phil Spector famously told David Susskind on a TV talk show, "What you're missing is the beat."
"Rain", by The Beatles, is a good example. The song uses a vocabulary of only forty-four words. The lyrics, taken by themselves, are negligible as a poem. Yet I think the recorded rock song is one of the greatest of all time. But it is the way the words are reinforced and extended by John's vocals, by Ringo's drums, by Paul's bass, and by the recording studio, that make it work as a piece of rock music.
6. What are the basic elements that comprise an enduring rock song? Conversely, is there a sure-fire formula for a bad rock song?
Well, I think, almost by definition, any song that is formulaic is going to be bad. So if you want to write a bad rock song, any formula
