On the one hand, I certainly struggle to see how more crowds will improve upon what is fundamentally a problem with crowds to begin with.
On the other, Wikipedia seems to work reasonably well--and purely as a result of the community mores, not due to any sophisticated moderation algorithm or ranking structure or similar.
I'm not holding my breath, but it is interesting to see if a community-driven effort imbued with a Wikipedian-like spirit might succeed where more automated efforts have not.