And HC was good in the scene when he and Obi-Wan argue before the duel.
But even in life as a house he has that monotone (well I can't explain it real well), like he's acting, You can't emerse yourself in his character because you think he is not real.
But I think the main thing is Lucas picked him for his look and not necessarily for his acting ability.
I'm sure you saw the doc from the TPM DVD with the cast auditions. Lloyd was just horrible and it seemed like he would have a problem with the strange dialouge and Lucas was like "This kid is awesome" How good of a choice was that