I, for one, am glad the show is cancelled. It was, for the most part, historically inaccurate, as well as, in my opinion, ridiculous. It started out a decent crime show, but turned into a soap opera with bits of action.
I didn't think its historically inaccuracies were all that bad given that it's a pop historical fiction piece. They did a good job getting the flavor of the period and even inspired me to look up things on more than one occasion to learn more about it. The Irish immigrant dynamic was quite good, imo. What particularly bothered you?