I disagree with specifying the original. There was a later cut (I can't keep them all straight) that made it much, much clearer that Deckard was a replicant. I thought that was obvious in the original but lots of folks didn't see it that way so the later edit was useful for those folks.
My only watching of Blade Runner was The Final Cut and I didn't get that impression at all. Maybe I just missed it or maybe I just leaned in to him being a human because it makes the story more interesting.