Yes, Kaori's very small talk with Shiori after the cafe party was EXTREMELY weak. I was really hoping that it would be executed so much better, but it just ended up as a disappointment. However, everything else was completely fine with me.
Regardless of this arc easily being my favorite, I admit that it's the weakest in terms of story and character development (there, I said it, haha). Makato had the happiness = death situation, Mai was tormented by her past, but Shiori just had a simple "I'm going to die at this time, so I'm going to do what I have left." Very simple compared to what we've seen so far, but it's something that we can all probably relate to the easiest. Well... technically, you can relate to pretty much any story, but you know what I mean... hopefuly, haha.
I'm very tired at the moment, so I may have rambled nonsense somewhere in there. I'm prepared for flaming, haha.