Has anyone considered doing a more structured, we'll call it, style of multi verse. Lemme preface by saying I'm not savvy to the current going on of the Arena. 

What I mean by a structured style is instead of, 'Hey, this is the overall story, go in and have at it.' It would be something like, "This is the world, in this thread the story is -insert story- and each character would play a role. for instance. One group would be trying to retrieve a mystical artifact from a ruined temple, while the other side is either attempting to do the same. Or trying to defend it.' story over. Thread ends. 

The main problem I've seen with our versions is that they tend to be open ended, no apparent end game, so they just taper off. People are able to create their own stories, and hope that someone comes along and competes with them.

In my suggestion, the stories are provided, rules are set by the GM(either an overall one or the thread creator), and the story progresses. Results get posted in a large timeline, so it's easily followable. 

This is just the gist, as I am currently on a small break at work.