It's not really about creating a new vision of an old movie. It's about making money. Vampires are big money right now, and with Let The Right One In having a fanbase (of what size I am not sure), there's some guarantee that between the vampires and the existing fans of the old one, there'll be a semi-decent turn out.

Now, whether or not the movie is any good is a different matter. The reason they're making it is the money.