You are right, Mike—metaphors are always risky. Especially when shared between friends who delight in tweaking each other’s metaphors. So, with all due respect, let the tweaking begin.
First, I love the symphonic metaphor. Second, I agree that there are various movements that flow through the piece to create dramatic point-counter point essential to the quality of the music.
I’m not so sure about the conductor. Who would this be? God, I assume, is the composer, and while the composer could also be the conductor, I assume that since you didn’t say that, you didn’t mean that. So maybe Jesus is the conductor. But Jesus, having left the symphony in the hands of the Holy Spirit at Pentecost, makes for a poor conductor. So perhaps it is the Spirit who conducts.
Even if we could agree on who the conductor is, we still have the problem of the orchestra rebelling against the conductor’s direction. A good symphony follows the conductor’s lead. If they don’t, the orchestra devolves into chaos and the conductor is out of a job.
Maybe the problem is solved if we shift from symphonic music to improvisational jazz. As I understand it, jazz has a core theme off of which jazz musicians improvise riffs. The riffs cannot ignore the theme, but they may oppose it and offer contrast to it. Such music is often highly discordant, and that would make the metaphor all the more apt. It is also created on the spot. In this metaphor there is no conductor, and God the Composer only sets the theme and waits to see where the musicians will take it. Maybe this is why God refers to himself in Exodus as Ehyeh asher Ehyeh, I will be what I will be. Even God is surprised by where the music goes.
What I like most about the music metaphor (regardless of musical style) is the need for rests and the goal-lessness of play. Music without the silence of the rests is just noise. Organized religion (as opposed to mysticism) makes little room for silence, the deep silence that frees us from the fixed notations of theology and ritual. The music metaphor would allow us to honor the silence more.
As for the sheer joy of playing, unlike most things we humans do in life, getting to the end of a piece of music is never the goal. The play is the goal; the journey is the thing. Otherwise the best symphonies would be those that played the fastest, and the greatest composers would only write endings.