I think the biggest problem is, when the
graphical detail in the faces / body is too high,
but the animation of it too basic.
This makes the viewer expect more from the model, than
the model can display - making it extra unbelievabe.
Its better to have a stylized body and face, but
then a more advanced animation, than the other way around.
This is what pixar is dooing. The characters are stylysed,
but the animation is very humanlike.
In "Being John Malkovich" there is a puppetplayer.
While the puppets are very stylized, they somehow
seem lifelike, as they are animated (string animation

very skillfully by the puppetmaster.