It may have to do with the attitude we approach box art with as opposed to the attitude other countries do. American Game companies (or the advertising firms they might hire to design the box art) don't care as much about the box art. So what you end up with is a cookie cutter "by-the-American-advertising-book" art that holds no artistic merit and doesn't give a clear impression of the game. I also don't just believe its just about identifying the main character because some of the American art is pretty bland in contrast to their international counterparts .Its pretty obvious that they're just not putting as much effort into it.