I think it's important for the GM to have some authority, but not fiat authority. They need to remain true to the world, they need to be fair to players, and they need to be a fan of the players, giving them challenges to test their mettle but not being an adversary who wants to crush them...because they're an adversary with unlimited narrative power.

Well, okay. There's a lot I can say about this. But basically--I don't think "DM is god" is necessarily a good dynamic for the game. I think...

The best way I'd term it is that the GM is a steward of the story and the game world. Their job is to keep the world spinning, and to set the players possible courses of action to trace through.