3D animation - Uncanny Valley

I recently watch The Polar Express, as we had be told about uncanny valley, and I understand what is meant by is.  

There's a fine point where something is made to resemble an actual human being but because it's so life like, but not quite a living breathing human, we find it extreamly uncomfortable. An example of this in animation are The Polar Express, and when I was watching it, although it was pretty good, there was just something off putting about the characters, like they were missing something, it wasn't appealing to me.

And I read that ways to avoid being in the section of uncanny valley, is to play with proportions. Avatar for example, their faces, you can tell it's Jake Sully, but it's not off putting because as an Avatar, his body is longer, ears are higher, nose is flatter, it's appealing because it's not made to look exactly like a human, but made to look realistic along with live action.