i think alakim may be right about the point values degrading. It used to be "For a given Search Query, how relevant are the 30 shown items?" for 12 points. Now its "For a given Search query, how relevant are the 36 shown items?" for 8 points. Oh well, Im still gonna do it anyways...
They are just testing how low they can go until users quit working. The pay already is very low, even when they offer more points. I refuse to do any of those offers because the work required doesn't justify it, not even if you just do it to waste some time.
That aside, crowdflower doesn't seem to be very interested to help users who complain either. Their support forum has quite a few posts from people who ran into problems and only a minority gets answers.