It's probably not my place. And if I'm speaking out of turn, by all means, say so and then ignore this post.
I think it might be a little difficult to keep running and for noobs to be involved when you have so many characters. If there are 12 posters, for example, each with their character, you have 12 characters. That's a dozen people you're trying to keep in the limelight and give equal attention to. Now, add in the minor characters each writer has tagging along and toss in some regulars from each rogue's gallery... and you've got quite the heady roster.
If you have a sorta... status quo... Just six characters, for example, and kept that, so that all posters wrote for those same characters (instead of a new writer bringing in the additional character, et al) then you could concentrate on the story of this handful.
Then in the talk threads, brainstorming and such can keep the stories on a linear plane, allowing different writers to move the plot. Plus, if someone stops posting, you don't have to worry about their character(s) having to be drug along because they managed to entrench themselves into the plot before buggering off. You can just move on with the same cast of characters.
This is all, mind, just the observations of someone who has watched idly from the sidelines. It is very well a possibility, that I don't know what I'm talking about and will take no offense to being told just that.
