In some ways, Hauer stole the show from Ford.
You're right. He could have been over the top without too much effort but he played it just about perfect.
I'm also a fan of the late Brion James, who like Slim Pickens showed you don't have to be a pretty boy to make a living in showbiz.
I think he did, definitely. Ford has never been one of my favorite actors--he's more of a personality than a real actor, and a dull one--I could think of ten other actors that could have done a better job as Rick Deckard. But Rutgar Hauer is a truly unique, quirky character actor. He was perfect as Batty.
"That's the spirit!" and "That was very unsportsmanlike of you..."
I know Ridly Scott has been ridiculed for his use of smoke-and-haze to ad texture to his films, but I think it really works in Blade Runner.