Motion-capture is probably even more difficult to do, since you have a lot less to work with.
However, not only should Serkis get credit, but also all the tech people who had to put all the digital stuff together. (I don't know any of the technical terms for that) I know I couldn't do any of the computer-y stuff anymore than I could do the actual acting.
Motion capture is as much art as it is science. After having worked on the art and animation side of a few small movies, I can really appreciate the amount of effort and money that went into the motion capture work on Gollum. It's well and truly
insane.