I also find his writing repetitive, but I realized that I have grown as a person too over the last ~3 years that I was reading his blog, what seemed inspirational then seems repetitive now, because I have grown out of those concepts and most of it doesn't apply to me anymore. Maybe he was able to sustain his willpower because he is repetitive?
I used to listen to Dave Ramsey a lot years ago to get some motivation and get certain things drilled in to my head. After about the 300th show, I could tell you about 95% of the time what he was going to say, almost word for word. That doesn't mean it's bad or he's repetitive (well, he is) but that it's 'worked' already - I don't really need that type of motivation in my life as I once did, as it did the trick.
"Abused by your father? Find yourself lusting after children? Hey, just stop! It's that easy!"