Huh. I've always thought Harry had a lot of personality. It's just very mental, i.e. he holds himself in check when weird suggestions pop into his head. Case in point the time when he wanted to knock the anti-werewolf potion Snape made out of Lupin's hands. Also keep in mind that he's been thrust unexpected into a completley foreign world after being raised by the Dursleys. This would probably make anyone reserved.
However, none of this is true for the movie Harry. Hate that kid. Everyone else is cast perfectly. He just doesn't look freaked out and clueless enough.
And the same thing is true for the book Draco. He's sorely underused and when he is, he's just a petty bully. Que lastima.
