As a songwriter I found myself agreeing with something Tommy Walker said about writing songs. Here's his quote from christianitytoday.com:
"Well, just to plug Chris Tomlin, it's not easy to write an incredible song that's also simple. He is so good at what he does, and I totally give him props for that. As to whether the song is simple or difficult to play, who gives a rip if it's hard to play when no one wants to hear it anyway? A great songwriter knows how to write a melody that makes you want to push the repeat button. That's the definition of a great song."