Is there any information domain where the open, world-writable wiki model can't be beneficially applied?
I think the answer is clearly "yes" and is based on the meaning and usage of the information. When the information domain has an objective authority, then community consensus is harmful. For example, legal contracts come from a single source - the participants. Although it would be useful for me to modify the terms of my car loan ("I'm going to write me up a minivan!") whenever it was convenient, I doubt that will ever happen. Another example would be prices of items listed for sale, which is in essence a contract for an 'offer to sell'. There is a clear authority for the offering price - the seller of the item. This shouldn't be confused with the 'going market price' for an item. That kind of price has no objective authority and actually seems to be defined by community consensus itself.
Some data in an information domain is synthesized or summarized from a set of other data - for example, the market price of an item isn't an actual amount offered by any indivdual to buy something. I wonder if a world-writable wiki is beneficial only in areas where meaning can be preserved by selecting one value from many choices.