Yeah, my views have changed of the characters since I last posted. Here's what they are currently:
I think it's safe to conclude that I hate this cast of characters and have not seen a group this unlikeable since The Social Network, mostly for the reason that I find them either boring, half-assed, or downright miscast. Mostly though, it's because the characters are just slaves to the writers. And I mean they're REALLY tools of the writers. The concept behind them is fine, but the execution is just plain horrible.
Spoiler for Shu:
It's safe to say that Shu is one of my most hated anime characters, but not for the reason most people hate him. Shu is the only character in this series that is properly developed/expanded on, so he's really the only character I can talk about. But unfortunately, he should have put in a better show, because his development in this really backfires on him due to either rushed execution or the writer's inability to decide whether he should be relatable or not. The only time his development becomes tolerable is after his arm gets the ax, but by then, it was a little too late to really appreciate it. It's like if the show started out with Shu as his current confident self and how he became that way wasn't necessary. Some characters can pull that off, but Shu isn't one of them.
People have been saying that we would not have done any different if we were in his position. You know, that's not really a defense, as I don't want to see me as the main character in this show. But even then, what kind of normal high school teenager has girls crushing on him for the weakest of reasons and gets rewarded for relying only on his Void powers? I sure wouldn't have been rewarded or respected if I did what he did.
In the end, Shu is a wimp that is the victim of poor writing and I hate him for being such an utter tool of the plot.
Spoiler for Inori and Gai:
But as much as I hate Shu, these two are probably worse because they're written more badly than he is. Inori is just boring. I know she's supposed to be an artificial human, but that doesn't mean she has to act like a fucking robot ALL the time. Besides, Gai is an artificial human too, and his development of emotions was far more convincing in just ONE episode (Episode 12). Inori just gained emotions because the writer said so. She should never have been the main female, as she doesn't even interact with Shu all that much. I forget she's in the plot half the time.
Gai, I never liked either. He's basically Shu if you replaced the wimpiness with confidence, but still kept the badly written character, dialogue, and everything that makes Shu boring. Him dying actually made him more interesting, but then they screw that up by bringing him back and made him such an utter tool that even the bad guys are aware of it. It's like somebody else took over the anime after Episode 12. What the hell?
In the end, I'm kind of amazed I hate this cast so much. I will say though that if the show had been a little better, I would have said that the tolerable characters could have saved the anime for me. But unfortunately, the writers won't give them their independence.
Edit: And yes, I agree with Triple_R that the characters have their roles to fill and half of them do fill them fine (That serial killer kid who barely does anything is NOT one of them. And don't get me started on that Daath kid). The problem is, there's not much to them besides those roles. I ask myself with characters, would I want to see stories about their daily lives. The answer is "no", of course. And while I do agree with Ledgem's analysis (although I didn't care about Hare's admittedly well-done scene because I hated her), it's one of those things that is good when written, but when watching it, I just go "eh". It wasn't bad, but it didn't leave much of an impact.