It is a slow book. But I think it lends itself to film better than most of the other books in the series. It has the biggest upside, I guess. I think it could/should be visually stunning and it'll be the shortest of the films. There's a lot that can go right with Gunslinger. It's everything that comes after that makes me nervous.
At least on film. The books get better... but the potential for ****-up also exponentially increases.