Blade Runner 2

Over on /Film they've discovered that Eagle Eye Co-writers are working on a sequel to Blade Runner. Can you imagine that? Whilst it sounds cool, and it'd be nice to see more Blade Runner, would it be right to make a sequel? Most remakes of old films seem to turn out bad, and I don't just mean "oh, it's not as good as I remember it"-type bad but astonishingly bad. I can name three films that say a sequel shouldn't be made:

1. Alien vs. Predator
2. Alien vs. Predator 2
3. The Phantom Menace

Is that enough proof that a sequel shouldn't be made? I thought so.