Experienced tabletop game fans might muse at the 'tavern scene' idea, which is a generic situation that pulls characters in a story together. Too many people scattered in distant places can create a sinkhole for character interaction, and that can sometimes lead the characters' parts of the story feel hanging on the edge.
It's not a hard and fast rule, and such an implementation is not always necessary. I've been in numerous RPs and they managed for the most part to find solidity in some part of the core of the story. It's these natural sorts of gravitational pulls in co-writing that I find myself fond of, but it doesn't always happen.
I guess it might be fair to say that, in a RP, no author is a rock. There will be generic 'loner' characters and sometimes people slip through the cracks. The hope remains that these characters have enough of a setting to meaningfully contribute to the story as a whole. As well as enough ink in their pens, if you catch the metaphor.
What am I getting at with all this rambling? A little bit of pre-game set-up is never a bad thing. It's fun to just make characters and see what happens, but when we find ourselves having trouble gravitating towards a continuous and consistent story; people get lost. It would be nice if we could play through and bring a story to a finish more often.