I understand there is some give and take with how I ask my questions and analyze the results (ie: what you put in is what you get out to a certain extent) but it would be awesome to be able to pay more and limit your users to specific countries or regions (if this means moving off Amazon Turk so be it. I would pay much more money than you are currently charging for a higher quality service).
"It's OK to be negative; I am looking to improve my site and any criticism is welcome. You actually have a chance at a bonus if your criticism helps to improve my site."
Sadly, some people need permission or an incentive before they feel comfortable giving an honest answer.