Story Is Structure
For a story to succeed, it needs structure. This structure either comes from the GM, or gets distributed among the players. Some gamers enjoy loose structures, others want more rigid structures--but if you want a story, you need some type of structure.
There are many parallels between how people structure their games and how authors plot their books. If you read several writing books, you'll quickly find that different authors have different theories. Some claim you should make detailed outlines and pin down all the information about your world before you begin. Others insist on a looser style. They want to start with a blank page, and just start writing. Let the story emerge organically. Often, the proponents of both sides argue that their way is the only way. In truth, there are advantages and disadvantages to both. Each writer needs to find their own balance, and most writers fall somewhere in the middle.
Outlining typically results in a better plot in the first draft. The story emerges in a well-organized, thought out manner. You can also uncover many problems with the story during the outlining--allowing you to fix them early, or preventing you from wasting time on an ultimately flawed idea. The downside is, if the outline becomes too strict, it can make the story feel lifeless and sterile. To be successful, the writer must use the outline as a guide but allow the story to drift where it will.
Freeform stories often have a more organic, more lifelike feel. They also typically need extensive editing. The first draft is really a discovery draft, letting the author explore the ideas. One of the real dangers of freeform stories is that the author will reach the end and find that there is no real story. This is a particular problem in the RPG context, since your ability to edit is very limited.
Traditional games tend to fall in the outline-everything camp (what I'll call highly structured games). The GM has absolute control over the world. The players act within the GMs world--and often the structure severely limits their choices. In the worst cases, the GM imposes the plot upon the players. The structure becomes so stifling that any spark of story suffocates and dies.
Many newer, Forge inspired, narrativist games fall at the organic end (loosely structured games). This includes several Gmless games. The games tend to be more democratic--players have a greater role in creating the world around them, and the story emerges from the player's interactions. In the worst cases, the story has no center and just falls apart. And, with several different people contribute to the story, it can be hard to fit all the pieces into a coherent whole.
Similar to the writing examples, neither gaming style is inherently better than the other. They both have their strengths and weaknesses. And, I suspect, the best stories come from the middle.
For me, GMless games make me uncomfortable. I like knowing that there is one person at the table who will ensure all the loose ends get tied up. One person who knows all the mysteries. Who can dole out important clues.
I don't trust that a well-plotted story will just emerge. Too many things can go wrong. In my experience, GMless stories are often lack coherence and focus brought by a GM. Worse yet, as a player, I either find myself competing with other players for control over the game's direction--or I just shut up and become too afraid to contribute anything. Neither approach is healthy or fun.
Now, in full disclosure, I must say that I have never played a published, GMless game. My opinions come from ad-hoc experiments. Many people enjoy GMless games. But I need more structure.
On the other hand, I also don't do well with stifling games. My character's actions should have a visible impact on the world. My decisions should matter. I should be able to contribute NPCs and locations, as long as they don't contradict those things the GM has already established.
I also feel that the GM has obligations to the players. As I mentioned in a previous essay, you can't bring a pistol on stage, unless you're going to shoot someone later on. If my character's background introduces a younger sister, then I expect the GM to bring her into the game. She should be captured, turn evil, whatever. The GM must weave these character-introduced elements seamlessly into the overall story.
OK, I will take off my writer's hat and put on my Computer Science hat for a minute. I've worked a lot on AI and Alife. Chaos is a commonly recurring theme. Too much randomness and the system falls apart. Too little and it smothers and dies. Somewhere in the middle is the Goldielocks mixture--that's where interesting things happen.
Tracy Hickman compares this to gripping a handful of marbles. Squeeze too tight, and the marbles pop out between your fingers. Too loosely, and they roll everywhere. I suspect he cups his marbles a bit tighter than I do mine--but it's still a good metaphor.
Interesting things often happen at boundary conditions: water at the freezing point melts and re-crystalizes in interesting patterns. Similarly, I feel that there's a fuzzy boundary condition between highly structured and loosely structured games. Here, the players have enough freedom to become full participants in the story, but the GM has enough authority to impose structure.
For me, this is where stories happen.