A follow-up to Carmack's Doom animation comment that was missed, as Jim Dose also chipped in with his two cents on manual animation versus parametric animation. You can read that post here

When I originally discussed what features we wanted in the animation system with the animator, I suggested adding controls for parametric facial animation, and he was basically horrified. His response was that he could do a much better job by hand. "This (animation) is what I do.", he said. After seeing the results of what he can accomplish by hand, I tend to agree.
I've looked into the research that's been done on parametric facial animation, and while it's impressive, I haven't seen anything that approaches the quality that an animator can do by hand. Even when the set of expressions it uses are manually created, the expressiveness doesn't compare to the subtlety an animator can put into it. ...