Pulpmeister, I completely agree that some types of story must need a good outline - mysteries/whodunnits, action-thrillers. This is largely what I had in mind when I was speaking of event driven stories - one or two characters may have certain twists that are important to the story, but most of the rest are there for colour/interest and can be changed out or merged with little change to the outline.
I have (I think successfully) dealt with converging threads in all my books. I knew they were going to come together again, but I didn't have anything more than a vague idea of how they were going to do that when the separate threads were created. The key for me was maintaining an after-the-fact outline (well, multiple overlapping outlines), so I always knew exactly where all my characters were in relation to the others at every point in the story. They all made it to where they were supposed to be (and without having to pull a hamstring to slow one down
).
The Wodehouse details are interesting, I hadn't read that before. I sort of like the idea of casting the story in advance, I hate it when I get to the point in a story where a new character is entering and I don't know them well enough to even give them a name. Everything grinds to a halt while I think about who it is that just walked onto the set.