Shea's 3X5 adventure design method actually has been very ideal for me. Since January of this year, I've been running a Mini Six campaign for my home group using this method. It's worked very well. I've delivered some of my best sessions from a GM's perspective. And my players are getting into the story, too. Win-win!
But it did limit me somewhat when it came time to start writing adventures for conventions. More involvement in that arena has been a goal of mine this year. And I felt a need to approach those games with more forethought.