I agree that fans will pick up more on the first viewing. I think it’s a really good adaptation, which is defined as one that stands alone for those who didn’t read the book, while not leaving those who know it saying, “what happened to my book”?
I also saw Dagny as dark haired. Bridget Moynahan would have worked well for me. Which reminds me, there’s a great Bill Goldman (if memory serves) story about writing a screenplay in which he described the character as brunette, and having the studio take a pass because they wanted something for their blonde actress. Repeated attempts to convince them that all he had to do was change the description of the character fell on deaf ears.
I’m pretty sure that Dagny was described as having jet-black straight hair. It would have been easy enough to outfit Taylor Schilling with black hair, and for whatever reason they chose not to. I can live with it. Schilling did a splendid job in the role.
I think casting Grant Bowler as Rearden was excellent.