The advantage of this is that people can have a go at a bit of game-making for a week, and will only contribute if they're actually interested enough to volunteer (which means they will do something). The time per person (1 week) is kept relatively short to encourage actual progress, rather than letting it get bogged down with designing new-for-the-sake-of-new systems (not to mention keeping things going relatively smoothly if someone vanishes). Meanwhile, the thread for the project will have discussion about the latest week's changes, collaboration about the story and so on, and will help direct the suggested progress of the game - the current week's developer still has absolute free reign over everything, of course. In the end all the revisions and possessions and discussions should come together to form an actual game.
Obviously someone needs to start things off first, perhaps before even making a thread for this project (so there's something to start from). Or maybe you could say that the Essentials example maps are the starting point, rather than starting with a blank slate like normal, and for starters the aim is to expand/turn them into an actual game (plans can always change later). I don't know whether it's better to let everyone download every week's revision, or whether it should be passed privately between each person as their turn comes round (the project's coordinater should also keep every revision for archiving, which is their only purpose). Everyone should definitely be kept informed of all the changes made each week, though.
Could this work?
for something like this to work you would need a foundation, an agreed story/plot, tiles, and what not. I dont see it working if yu have no foundation to build from, if you don't it'll probably become a huge mess that doesn't make sense