There should just be a gameplay version of a captcha test -- some random element built into the gameplay that only humans can pass. Content that can be passed by sub-human intelligence with no consciousness is not really fit to be used as entertainment by real people. Machines are much better at menial, repetitive tasks. The current gathering system is similar to working on a production line. Making a more complex system doesn't have to mean lower yields; it could simply be a fun and engaging mini-game that takes slightly longer to produce results, but accordingly yields a much larger amount of materials for the extra time invested.