I was less impressed with Season 2 but I was impressed of the willingness to follow through. I think the series as a whole was superb, particularly when it showed the small town in a way never truly recovered from the blow of the murder that started it.
I think overall it features David Tennant's single greatest performance in television and I do this with the acknowledgement that he is one of the most outstanding thespians in British and American TV. I once wrote in my first review of the show: Tennant seems more out of touch with his humanity then he ever did as the Doctor, more grounded and more riveting. And this was my first experience with Olivia Colman who has never disappointed me in any performance she has given in film or television since then and must now be considered one of the greatest actresses working today in either medium. Only Keri Russell and Tatiana Maslany can match her when it comes to constant brilliance in television excellence as her contemporaries; only Saorise Ronan and Jessica Chastain are her peers in movies for consistently brilliant acting. And much must be said for Jodie Whitaker's work throughout the entire series as well.
I intend to revist Broadchurch someday myself and I wouldn't mind if the show itself were to return for a fourht season. I know it was wrapped up neatly in its third year but these days that counts for little and especially for British series which can wait years between seasons (Happy Valley is the most recent example) I know Tennant and Colman are very busy but perhaps a new group of detectives could return and see what's happened years after.