In an interview from Amsterdam, Hauer told Hero Complex,

"If Christopher Nolan would be on it I’d say, ‘All right, go for it!’ But otherwise you can’t do it. ‘Blade Runner’ is such a unique film. How do you describe a diamond? I don’t think you should ever touch it again.”

It's interesting that Hauer didn't mention original director Ridley Scott, who is currently at work on Prometheus, his first science fiction film since Blade Runner. 

Also interesting is the fact that during production of Batman Begins, Nolan frequently cited the aesthetic of Scott's film as a primary influence.  Scott's film also seems to have served as inspiration for the director's Inception, with its open-ended interpretation of crucial thematic elements.

Broderick Johnson and Andrew Kosove of Alcon Entertainment captured the rights to certain elements of Blade Runner and 'Do Androids Dream of Electric Sheep', the novel by frequently adapted author Philip K. Dick.  They're not legally allowed to remake the film, but they can sequelize it and build off scenes from the original.  The film was not a commercial success when it was released, nor would it be likely to do any better nowadays.  Also worth noting is that the setting is 2019, which was plenty futuristic back in '82, but is a mere eight years away now.