As a parent, you end up watching a fair amount of cartoons, and...

I think this has to do with the fact that hand-drawn frames directly convey an accumulation of human-made choices. Each choice, from the initial design to the final brushstrokes, leaves an imprint, a trace of the taste and thought process of the people who brought it into being.
With CG, the human-made choices are both fewer (which is evident in the fact that CG is much less labor-intensive to create) and less direct, more mediated. Hence the lack of soul -- you are no longer in the close presence of the creators' minds.