Like his 'Star Wars' co-star Carrie Fisher, Harrison Ford appears to have come to terms with playing a character that he once couldn't stand. He decided to return to 'Blade Runner' when the movie received a sequel in 2017, but had he been asked to step back into the shoes of Rick Deckard ten years earlier, he may not have agreed to do so.
It seems to be the science-fiction aspects of the script that Ford had an issue with - which is strange, considering his 'Star Wars' role - but in the case of 'Blade Runner,' he thinks all the weirdness got in the way of the story. He also found it difficult to put his finger on what Deckard was supposed to be; on the surface, he was playing a detective, but as Ford put it, Deckard doesn't really do any detective work in the film.