Will there ever actually be a Blade Runner sequel? I would put my money on no, for all the same reasons you expect-- nobody actually wants it, the original is perfectly good, Harrison Ford is too cranky to consider it. Well, scratch that last one, actually. Somehow IGN got Ford to admit, in the midst of press rounds for Ender's Game , that he'd be game for the sequel. See it for yourself in this video:
"I truly admire Ridley as a man and as a director, and I would be very happy to engage with him again in the further telling of this story."
That sounds like classic press release language to me, meaning that Ford has figured out a way to address this question without actually committing to anything. Scott, on the other hand, has no problem chatting up the project, though he's been skeptical about Ford's participation in the past. Even with no commitment from Ford the project has been moving forward in bursts, and last May one of the five screenwriters of Green Lantern, Michael Green, was brought on to shepherd the script. If "Blade Runner 2, from the man who brought you Green Lantern" makes you a little nervous, maybe Ford's willingness to return can make you feel better… but then again, he's the guy who thought Paranoia was a good idea.
Again, I'm putting my money on Blade Runner 2 being one of those long-anticipated movies that never happens. Then again, I would have said the same thing about Indiana Jones and the Kingdom of the Crystal Skull. Sometimes there are bad ideas that Harrison Ford decides to make possible, and Blade Runner 2 may have just become another one of them.
