The film is an adaptation of a Philip K. Dicke novel done in film noir style in a futuristic setting. This style is difficult to pull off today since it has been caricatured for so many years. Yet Blade Runner does not really add anything new to it except the setting. Everything from the sleazy back street crime culture, to the lilting saxophone music, to the cheesy street-wise detective narration, the fatalistic love interest, except instead of a prostitute or struggling actress, the lady love is a misunderstood robot. Even the femme fatales are robots. Did Ridley Scott intend this to be comical? He did much better with Alien - oh wait, that was 3 years earlier. Harrison Ford was never a great actor, but I thought he was better cast as Han Solo in Star Wars and as Indiana Jones. The special effects were sufficient for their time, but after Star Wars set the bar 5 years prior, I don't think it deserves too much credit in that department either. And while we're on the big names, Vangelis wrote much better music for Chariots of Fire - oh wait, that was a year earlier. I am not saying that film noir can't be done effectively today. Just look at the narrative portions of the Watchmen as an example. But the key is that you need a real story to back it up. Watchmen starts with a murder mystery and leads up to a full fledged evil plot to conquer the world, etc. In Blade Runner, there's no real plot, no murder mystery, no twists of fate, just a cop trying to kill off the riff raff. The point seems to be to just revel in all things strange and grotesque.
2001 with its treatment of HAL the super-computer, so the concept is not new. Since that theme is an important part of Dicke's novel, I'll bet it is treated more skillfully on paper. But let's face it, the credit in that respect goes to Dicke, not the film. I do, however, give credit to Rutger Hauer, who played the replicant leader. He really captured the strange juxtaposition of the rage of a man sentenced to death with the confusion and innocence of a 4 year old child.
Of course, Scott released a director's cut that eliminated the narration by Ford, which he had never wanted in the first place but the studios insisted upon. I imagine that would be a definite improvement.