"I think he's underrated in that low-key role."
Absolutely. At the time he was typecast, and it took a serious reconsideration of both the movie and of Ford's acting for people to realize just how good he was in the role.
Now that he's got an extensive body of work in his career, more and more critics are giving his acting in the original Blade Runner the credit that it's really due.
Here's a tidbit that a lot of people don't know about the Deckard character... Harrison Ford wasn't the first choice for the role. Dustin Hoffman was.
Another tidbit... Harrison Ford doesn't much like the original Blade Runner. Didn't like the movie, didn't like working with Ridley Scott, and he HATED the last minute addition of the voice over (which I think really helps tie the movie together on so many levels, but I know I'm in the minority on that).
It took me several viewings of the various "definitive versions" to really comprehend just how incredible Blade Runner is.