Yeah personally I wouldn't trust anybody who does different accents for interviews depending on the film. Don't mess with his lights.
I think that hits it on the head for me. You can see he is really trying to act. You can just see his internal monolog saying wow look at me acting. I am fucking awesome.
I think Bale is good but suffers from, look I'm acting, can you see, good isn't it. You can never quite be drawn in. However there is about a billion well known actors worse than him.
That and the silly voices.