Great article. I thought there were some terrific choices.
"Never Played Symphonies" entry caught my eye because it brought up the notion that a Morrissey's song couldn't (or shouldn't) be covered by other artists because they are too personal. Many artists claim that Morrissey's appeal come from the idea that his songs address common human experiences, so why aren't they covered more often? I think it would be very brave to try.
Bob Dylan songs are great and have been covered by just about anyone, but do they speak to more people than Morrissey's songs?