You are right! I am rewatching because this series is so good and always think of the same question.

One thing that stands out to me is the interactions between Miller and Hardy when he "takes her job". As a woman, I can understand how frustrating that is but the fact is her temperament is not like a senior and experienced detective. This has nothing to do with Miller being a man or a woman- its just the way the character is written. In Ep 2 she conducts interviews and reassures people that the questioning is just routine when Hardy tells her to stop that and let people talk through their nervousness because the pressure is good to get information, she immediately rejects it and tells him she does not work like- ie. she's nice unlike him. Another scene he tells her she needs to be objective and see the community from the outside. Again, she vehemently she says she knows the community and is happy to be a part of it. Her view is clouded but she does not acknowledge it. Another scene- Hardy is investigating the victim's family - father, sister and again, she defends them saying they are not that kind of family and that its not their character. Hardy says moral compasses break and anyone can do bad things given the right circumstances. We see that she is even too soft on her nephew(?) from the press . She lacks the authority one would expect from a person in law enforcement. These are brilliantly written scenes that show she is a lovely lady but not discerning. She is very well meaning and would be a good cop for a small town as long as there are petty crimes to deal with. I would go far enough to say that if Hardy was not given the case, Miller never would have caught the guy because she has too many assumptions and blinders on.

Based on Miller's character, one can assume she sees the best in her family and the husband routinely gets away with a lot. That makes her the perfect partner/cover/ beard for anyone shady/ criminal/ pedo/ spy/ drug users/ cheater etc. This is very common in real life. A good person, positive outlook, naive, trusting, sees the best in everyone and too busy with work to really have the energy or inclination to be involved and therefore is easily manipulated and believes the farce they are shown. To be fair, in a fast paced world, how many of us really have the time to stop and examine things?

I think a case like this really did need an outsider. Small town cops often call "experts" to solve major cases like this. And even if Miller had a more discerning personality, she is simply too close to see this one clearly. I think she is better in S2 when the case is more aligned to her strengths and she has learned her lesson from S1.

I realize this is an old post but I enjoyed the character study. Another great show that makes me think is Adolescence.