While this article is partially about "Mars Needs Moms" and how it has kinda bombed in theatres, I found the part about the "uncanny valley" interesting.  As animation becomes more and more realistic, or "human", people begin to dislike it more because of little flaws that we may barely notice but subconsciously reject.  Things such as the "dead eyes" are commonly noticed, but often skin tones or texture being slightly off creates problems for people accepting it as well.

http://sync.sympatico.ca/news/too_real_means_too_creepy_in_new_disney_flick/4c8713de

This same phenomenon has been talked about with regard to robots too.  There are some that are extremely realistic, but the little imperfections make them seem creepy.