People like super heroes who are a live example of their needs and deep desires. Most people want to be strong, powerful and muscular. Batman is a superhero that combines all of those traits and so satisfies the needs of the people seeking power and strength.
Most males want to be dominant, more manly and masculine. Batman has a very deep voice, his suit makes him look like a well built macho man and his angry face reflects many of the masculine traits males are eager to have.
When a person watches a movie he unconsciously believes he is the hero he is watching. Batman is one man but the city usually begs for his arrival to save them from evil. The idea of being able to provide support to a whole city, to be needed and superior appeals to so many people.
Ninjas are very popular, especially among males. When a hero combines the popularity of ninjas with his own attractive characteristics he appeals to many more people.
Batman is a mysterious and unpredictable super hero. He hides in the dark, appears out of nowhere and covers his face with a mask. Studies have shown that mysterious people are considered more attractive than predictable ones.
Unlike other super heroes who might not be human, Batman seems more realistic to so many people since he is just a talented human. While Superman is an alien, Batman is just a person who has some really good skills and a very attractive outfit.
Batman's car, his bike and his weapons are very interesting. The fact that an attractive super hero has attractive weapons made him more popular.
The Symbol Batman uses sums up all of his powers. When people see the symbol they remember everything great about batman and so like him even more.
Batman has an ethical code, he does nothing wrong, he harms no one and saves people. He is a perfect example of a super hero who abides by an ethical code.
Batman is a super hero who is rich, handsome, successful and attractive. Unlike other super heroes who don't have a life outside of their outfits, Batman is a man who has it all.