Other than what I think is unnecessarily graphic cruelty, I think that I've finally pinpointed why the BLUE motives (especially chapter 3) are odd to me.
The point of Danganronpa (at least, the original DR) is that the motives are meant to be things we as the audience consider weak. We're supposed to think, "A couple thousand dollars isn't worth a human life. A random secret isn't worth a human life. Group conflict isn't worth a human life. Why would any of them kill each other?"
One of the biggest themes in that game is that, no matter how small or unimportant something might seem, there's someone it matters to, perhaps enough to commit a murder. You can't assume that everyone has the same morals as you do, and you can't assume that even the best, most reasonable of people don't have things they'd kill for.
The "despair" in DR1 is based on the idea that humans are naturally willing to betray each other over such seemingly trivial motives. It's a Death Note situation where the audience is meant to think that they wouldn't commit murder because murder is wrong, but the point of the narrative is that, no matter how stupid it might seem, no matter how normal a person might be, they are still susceptible to immorality. The "hope" in DR1 is that even when there's a natural human inclination towards selfishness and cruelty, there's also a natural human inclination towards kindness and mercy.
Obviously mainline Danganronpa isn't perfect, but that's the premise of the first game, and it's one I think works quite well.
The motives in BLUE (and in parts of PINK as well) rub me the wrong way narratively because a lot of them essentially necessitate murder. Which, while that works sometimes, can feel like it's almost robbing the characters of agency instead of highlighting it. Logically, this is what a person would eventually have to do, so it doesn't really feel like a point is being made about human nature. "Humans, when left to their own devices, can and will kill each other over personal stress, grievances, experiences, and motives, no matter how small they may seem" is, in my opinion, a much more emotionally compelling story than "Humans will kill each other in order to avoid even more people, including them and their victim, suffering and inevitably dying," because the latter makes the motive too logical. You don't wonder, "Would someone kill over this?" You wonder "When will someone kill over this?" And, while there are definitely benefits and interesting aspects to both (for example, I actually quite liked PINK chapter one's motive), the ways that Tetro works with that second idea sometimes come across as, in my opinion, lackluster.
I don't know, that's just what's on my mind right now. Might delete this later.