The good vs. evil motif is ubiquitous. I've seen well done forms of it, but the whole moral absolutes thing I feel belongs in a children's story. One thing I would suggest
avoiding is not tailoring the story around the main character. Don't have everything be guarded by means that the character is proficient in overcoming... make him need help, or fail a few times. And if you're going to go beyond superficial losses to the character, don't kill off the already tragic sidekick. That's just cliche.
My advice on writing a story is not to follow someone else's structure. Your story should be your own, not a thin veil you cast over someone else's.