Search Suggest is also dependent upon the volume of content related to those keywords. Remember, the original search suggest provided you with data on the number of search results available for the phrase. We have seen marginal improvement with just massive content syndication and no click manipulation.

Finally, whatever you do, it will have to be sustained. Suggest is updated alongside whatever keyword metrics Google is using. You can't simply hope to run a single mechanical turk campaign and then permanently influence the results.