It's a toss-up based on the trailer. It looks like Garden State with Jesus. Now, I like Garden State, but the trailer toes very close to the line of handling "The God Issue" deftly and just tacking God on to the basic indie film structure. Which is my major issue with Christian films, the formula becomes "X Genre + Jesus!" and like you noted it never works. I'm already skeptical of the scene where he's on the stage with everyone cheering. That said, if they nail the confessional scene they've nailed the movie. That story encapsulate everything that works about the book.  But after all that waffling, it is a trailer and only the marketing.  I'll see it, but more because I love Blue Like Jazz. 

And are we counting The Ten Commandments as a Christian movie?