They did a much better job with each arc this season compared to S1. In S1 they only had 1 real arc, Steel Lady Nanase and it got rather dull and boring because not much happened for how long it went on. With S2 it follows two main arcs Sleeping murder and Yuki-Onna's dilemma. These two arcs take up a few episodes each with there being 4 separate mini mysteries arcs in-between that are 1-2 episodes each. This made for a much more entertaining experience as you would get a fresh story with a new mystery ever few episodes. The mini mysteries stories were OK as well for just being 1-2 episode, but they definitely lacked any meat on the bone because of how short they were. However i found the main two arcs were a perfect length to get that meat on the bone and build up something interesting with decent characters. Yet at the same time they weren't long enough for you to get bored like in S1. It seemed to be the perfect balance and i enjoyed them both in comparison to S1. They are still lacking if you compare them to other similar shows arcs, but its a decent watch now.
The main saving grace from S1 is still the same in S2 as well, Iwanaga that is. She is still the same adorable, funny and intelligent girl. With her mind even further in the gutter this season when it comes to Kurou and her thirst for him. Some of the things she says this season to people about her desires and how far she goes had me cracking up. So you can look forward to her just being the best again this season if you liked her in S1 like me.