And often the things you want to map are better mapped seperately in their own dataset. Just consider woodland. Should that block of trees be mapped as individual trees, a block of woodland, or as a linear hedgerow? Different people would answer that question differently. A topographic map forces everyone to have the same answer.

I think that citizen mapping should move to focus on particular subjects and themes that the individual is interested in. And try and get closer to the underlying phenomena that is being described.