The beginning of this volume contains an event that pretty much completely changes the story, I can see why they'd want to do something like this after two volumes of the same set-up, but it was extremely disorienting. It felt like everything that had happened previously suddenly had no influence, and it was like the manga had somehow rebooted itself before it was even done. I had negative feelings about all this initially, but I soon began to really enjoy it. The event in question doesn't really change everything, and it certainly doesn't retcon the first two volumes, it just takes things in a much, much more complicated direction, and I ended up loving that.
The new focus on the Yotsuba group was a great way to reintroduce the classic Death Note Kira vs L chess game of outsmarting each other, and it concluded in an unexpected and enjoyable way. New characters add new dynamics to the story, but they don't feel shoehorned in. At this point there are so many elements at play that I feel like the battle between Kira and L could go a million ways.