- Five was a needed character from my point of view. It's the only character that grew up in the same place that Nine and Twelve, therefore the only one who understands how they think. You have a point when highlighting that the rivalry between them takes the series to a new level a little bit unexpected after the format it was following before. However I don't find it less interesting.
- Lisa, well, I need to agree that she's not my favorite character, but she's the link between the normality of the real world, and the terrorists. She suffers some kind of self-imposed Stockholm Syndrome, which leads to further development of Nine and Twelve, who seem to show a human side when they are with her (the final scene before... the bad thingy lol).
- Shibazaki comprehends the whole thing without even being part of the terrorist group. He event sympathizes with our beloved the Nine & Twelve after understanding what they seek. Unfortunately I do believe something was missing. For example many viewers (including me) thought that at the end Lisa would be his daughter, which would deeply link most of the characters into a circle. They decided instead to include Shibazaki's daughter as a new character that plays a minor role. A bad decision in my opinion.
Said the above, I strongly agree with you at something: the realism. I think when the story sacrifices the format it was following previous to Five's debut it also drops some stuff that made Zankyou no Terror more serious in several ways.
Even if I loved the outcome, it doesn't look very professional.