I can not think of one case of animation with dialog where other movments were animated -- on a sliding scale of realism -- but no facial animation was attempted.

There was this sci-fi cartoon series back in the late50s, early 60s (maybe? I think) that had zero facial animation but used films of real mouths imposed on the static animation; and yes, it was highly, highly weird. For the life of me, I cant remember the name of the show, but there ya are.

docandraider.com -- the collected cartoons of Doc and Raider