so, resting on a decade of D&D experience, I would suggest the following:
1.) people can still be surprisingly open-ended and creative, even with a restrictive ruleset.
2.) If you don't want people coming up with the result of their actions, someone else has to. In D&D, it's "I attack the kobold" and the DM says "you kill it". Otherwise, it becomes players saying "I attack the kobold and kill it". This leads to a lot of the minor problems that happened.
3.) D&D is packaged into scenarios. This makes it so that players are guided through a story, rather than wandering aimlessly with vague objectives and thinking up things to do. The reason I quit out in the middle is that I felt like I could read an entire page of posts while still getting the feeling that absolutely nothing was going on. Thus, I think that there needs to be a lead that actually drives the story, rather than it just sort of randomly going along.
So, in conclusion, I think that it needs to be set up with the thread creator (or a nominee) as the person driving the story (and presenting obstacles to prevent the players from easily achieving their objectives), and people need to get feedback from their actions, while being restricted from creating it themselves.
And you guys want a map? I'll spend the next ten minutes drafting something simple for you all, how's that?
EDIT: Allright. For those of you who think there should never be a map (and I can think of some good reasons myself), don't click
here. I say this as it's a highly abstract, scaleless, impression of what it COULD look like.