I'm on a panel about Pratchett tomorrow, and I've been thinking a lot about what's so great about his work. I think I've landed on something: he doesn't ever focus on the big picture.
I started explaining it to myself by metaphor, and I'm going to try and make that metaphor pan out here.
You know those pictures that are made of hundreds of smaller pictures? Imagine one of those, of a man about to throw a baseball.
Now, imagine each of the smaller pictures is a TV screen, with a movie paused somewhere so that rectangle works to make the baseball guy.
If you focus on the big picture, you'll think that when you hit play, the man will throw the ball.
But when you hit play, the man, the ball, and the whole picture disintegrate instantly -- because the big picture was always just a way of forcing unrelated things to seem unified.
Pratchett's heroes all focus on the small pictures, where outcomes are predictable, or at least within the realm of considering. Even Vetinari, the mastermind of all masterminds, doesn't plan. He "steers," and speaks out against pulling together, saying "free men pull in all directions." He doesn't try to make the city a utopia. He tries to make everyday outcomes shake out better for the people in general than they otherwise might.
The villains -- like Lord Rust, Reacher Gilt, and the dwarves from Raising Steam -- they're big picture people. They're ineffective and destructive because they try to tell the future based on an illusionary comprehension of the present.