I thought it had an interesting arc and was a natural evolution from season 1. While I really enjoyed the interviews of serial killers (and mainly Holden's reactions during them, that make him pretty fascinating and that underline just how fine the line between him and them is), it had to move onto something else so their involvement in an active case made sense. It was also good to see the arrogant Holden doubt himself at times, especially when realizing how high the stakes were. Tench's character is probably the most interesting of the three but the story with his kid was a bit boring, and Wendy was mostly just wasted this season. I don't think it was perfect overall, but it was really enjoyable, it's still as well put together (give me hour long episodes of Zodiac style directing any day of the week!) and it definitely begs for a third season. It's just going to be an excruciatingly long wait again, isn't it?