When I answer a question, I try to be as complete as possible. I also realize that I may not be as complete as I'd hoped.
Community Wiki answers provide an opportunity for good answers to float to the top, and for shortcomings in those answers to be rectified by folks other than the original authors.
But right now, the system discourages creating Community Wiki answers by denying all rep credits to those who create them. It also discourages improving community wiki answers by not granting any rep to people who do that. This means that the pattern that's encouraged is many separate and disjointed answers to each question, not one comprehensive answer that incorporates the bulk of the community's knowledge.
Combine that with the 750- 100-rep minimum to edit a Community Wiki answer, and I frankly don't get the point of the feature. It seems promising, but it just doesn't get used much, and it seems like the system, intentionally or unintentionally, is designed to ensure that this is the case.
So why was it designed like that? Should it be changed?