I don't follow the Academy awards or the various subdivisions of what is award worthy, but there should definitely be recognition to all facets of the film making process.
Is there a category for the voices in animated films? I know the actors doing the voices always get recognized and mentioned in the credits.
In Serkis case, he is the soul of the CGI ape (as well as Gollum) and should at the very least be included in the special effects part of that movie. In a sense, if he were an actor a few decades ago in heavy makeup so as not to look human, would he have been eligible for an award as that character.
I know John Hurt was nominated for playing John Merrick in The Elephant Man. Of course he did have a (strained) speaking role, but acting is not always about doing lines. So, giving credit to the computers and the ppl who use them to create images of characters, but when an actor is speaking thru that computer his performance should be recognized.