It should be collaborative; it is one of the benefits of a wiki.
Right now it appears it will be a very large entry. I would caution for large events, where there is a lot of detail, to build separate entries and include summaries and links on this primary entry (see wikipedia entries for things like
World War II).
It is important to relate to everyone taking part (both IC and OOC) to take and upload screen captures. Walls of text are fine and dandy, but images really make a page that much better. We need to tell those taking part that they can up-load them to evelopedia and add it either to the entry itself (at the appropriate location) or in the discussion area.
Also, some data mining info can be useful. A time table of the events, locations, etc, help make the page useful.
From a promoting RP standpoint, naming & linking to the organizations taking part on all sides will help to grow everyone's corporations, alliances, and organizations.
Also, a note at the top indicating whether it is IC/OOC will be equally important. The information provided on the entry will vary depending which medium is selected. I personally favor the OOC perspective for the entry as a whole with quotes from various characters involved being mentioned. The second benefit is that it will encourage players on both sides of the conflict to contribute.