God is like the author and we are like the characters, but this doesn’t work so well because the characters–their nature, their choices, etc.–are total creations of the author, and have no independent existence. The story is fully set, crystalized, solely from the author.
God as writer and director and Men as actors works better, since actors need to bring something from themselves into their characters, and even more so if some improvisation is allowed. Then the film or play is a creation of both the writer/director–writer role planning the story, director role bringing it about, executing the plan, providing the filling and details–and the actors–pretending to be the characters. But what the actors bring is still very narrow, and while this analogy includes the qualitative difference that there is some creative contribution from the analogised Men, it doesn’t satisfyingly capture the degree of possible contribution.
What is wanted is something that gives real and full significance to the choices of Men while maintaining the ultimate supremacy of God. Men are free to choose as they will, though they are extremely constrained on the actions they can take from their choice. And though God will always guide things as he will, this is not without influence from Men. God does not override the choices of Men, but incorporates them into his plan. The choices of men–good or otherwise–will be used as the means to achieve God’s will, with the resulting “story” being richer for it.
So God is like the Game Master of a paper-and-pencil role-playing game, like Dungeons and Dragons. He has a plan for how the game will go, and provides the world and orders its inhabitants and decides how they might interact, but the players are free to choose to do as they will within the game. Since the players don’t know the plan, the Game Master is constantly arranging situations and intervening “behind the scenes”, creating other characters and situations to aid or hinder the players or otherwise move the story along, but probably these interventions are best–in the sense of best story, most enjoyable game–when not heavy handed, when they feel natural and fit well with both the pre-intended story and the spontaneous choices of the players that arise from an ignorance of those intentions. This includes balancing the difficulty of achieving the intended hurdles, and an invisible hand that guides the course of the players towards the intended quests.
If a player’s character dies in a fight with an enemy, the GM could just bring them back to life, but this would be unsatisfying, because it removes the significance of what happens. A clumsy deus ex machina plot turn can ruin an otherwise good story. If the player knows that if he fails the GM will just fix it, then it doesn’t really matter if if fails or succeeds. On the other hand, bringing a character back to life might fit the story and world well in the right circumstance–as when Illuvatar intervened directly in Middle Earth to restore Gandalf’s life after his battle with the Balrog.
At one extreme, an RPG game where the GM just tells the players what is happening to their characters is not fun. At the other extreme, a game where the characters have total freedom is… not actually conceivable (not coherent, chaos), since they at a minimum need a world in which to be free, and this must be provided by the GM. Balance is maybe not the right word for a good game that avoids both these extremes, because a good game where a rich world and meaningful goals created by the GM combining (interacting on a moment-by-moment basis) with the free choices of players is not merely a midpoint or average between extremes but something more, the way adventure is more than just story.
Life is an adventure, and God is running the best RPG game possible, even if (or probably in part because) we don’t know the whole world or plan.