I've thought quite a bit about Wiki for "news." My feeling is that Wikipedia is already journalism, but not news. The Wiki concept would not be suitable for news because news requires a deadline, an end, a static form. It necessarily has to capture the state of affairs at a point in time. That's why mantras in the news business go: "Make air, not art", "Tomorrow's fishwrap" and "Better never than late [sic]"
Time limits don't serve Wikis well. Wikis are good for continually evolving content. An arbitrarily set deadline would drastically change the nature of edit wars, neutrality disputes, community and evolution.
I would equate it to an eBay auction where bidders having an infinite amount of money, because we all have an inifinite amount of opinions. :)
-Fuzheado