The reason why many people like the LEGO Batman more than the actual movie Batman is because in the LEGO Movie, the story's plot and character personalities are from a child's point of view, which means that this Batman is a very stereotypical and silly Batman, as seen in lines like the often made fun of 'I'm Batman.' This is the kind of Batman that we as kids enjoy, not some dark, edgy, and depressed Batman that the movies gave us. That's what I think, anyway.