This post is going to be very indulgent, it's basically me musing about how a DRV3 could've worked with Kaede as protagonist in comparison to Shuichi. Basically I have a lot of time on my hands.
Anyways, I mentioned it in the main thread but one thing I really enjoyed was how unlike Shuichi she actually had a discernible threshold for her patience, particularly in how after a point she would insult Miu back ("cow udders" is still one of the funniest things anyone's said in the game imo). She was way more assertive and had clear flaws, which is something I would've liked to see explored more. With the previous protags it always felt like the cast assumed so little out of Hajime and Makoto because they were by design meant to be generic. They were jack-of-all-trades that didn't really have any flaws in the context of the games themselves. But Kaede already had a huge impact on everyone early on after she motivated people to escape, and after everyone being thoroughly dejected by failed escape attempts there's a huge potential for an uphill struggle for her.
So here's the basis of the "What If" scenario - what if Kaede did go through with her murder plan but instead Shuichi accidentally goofed something in the basic outline of the trap which would make it so that he ended up being the killer instead? Chapter 1 would've ended on a fucking dark note, and I think that would be a great DR-styled twist because it means that Kaede not just brought everyone up to the top in the beginning of the game but also destroyed everyone's trust for her in the process. It'd be a massive spin on the Sayaka twist from DR1. Kaede attempted to kill someone, but because of outside interference, someone else takes the fall instead - and now she has to go through the entire game with everyone pointing dagger eyes her way, knowing that she is indirectly responsible for two deaths. Everyone would be more willing to argue against her in trials, and she'd essentially have to regain everyone's trust. In my mind I feel Kokichi would benefit much more from Kaede as a protag since he'll clearly notice Kaede's propensity for thinking outside the box in coming up with solutions, perhaps even wanting to get on her good side, and him being a foil to Kaito would be much more evident. Kokichi could essentially be reifying Kaede's more ambiguous traits, while Kaito is the other side of that coin. I think her also being caught up in that kind of situation can become a good reason for a kinship to develop between her and Maki, as we know that the both of them have exhibited a capacity to kill.
Another chapter I think would benefit a lot from Kaede as a protag is Chapter 4. Implicating Gonta in the confrontation with Kaito would probably be a lot more tragic, because if Kaito's "best bro" status is maintained in the story, it's possible that he'd be part of the reason Kaede could still recover from that aforementioned Chapter 1 twist. But in implicating Gonta there's a lot more personal weight to be had, since criticizing Kaito's naive altruism is by extension her lamenting the fact that throughout the process of the game, Kaito may have been way too easy on Kaede. Her guilt for having Shuichi killed never really goes away and there's no real way for her to know if she'll be absolved of it. Then in Chapter 5 we get an ironic echo to the first Chapter as this all gets turned around - instead of a case where someone accidentally ended up becoming the murderer, we have someone who decides to become a murderer to save someone else from accidentally becoming one.
And the irony of Shuichi becoming an accidental murderer? His DR audition tape explicitly has him saying he wants to be a murderer, because he wants to take advantage of his Ultimate Detective status. If Kaito's audition tape had Maki dance the trauma conga line, I can't help but imagine what Shuichi's would do to Kaede.
It just seems like wasted potential to me that there was a much more evident character arc with her, especially when they built many of the game's new mechanics with her ability in mind. It doesn't make much sense for a detective to lie, and the Mass Panic Debate is built around the idea that she can hear people better than others. It just makes less sense to me to have Shuichi use these abilities - particularly committing Perjury, because for Kaede to have done an attempted murder, it makes sense that she'd embrace the usage of lies in future trials.
Another thing I feel they could've used Kaede as a vector for is in further deconstruction of Danganronpa as a series since that's what they were going for. The only thing the game is explicit about calling out is the Hope/Despair angle, and don't get me wrong - I love the fact that the game does. It's another thing that I think would've made even more sense for Kaede to be the one to do that, because while it's never explicitly mentioned, her "hope" to unite everyone early in the game is almost instantly denounced, meaning she's developed out of just assuming it has to be a binary concept. That said, something I've always felt deserves calling out in Danganronpa is the idea of an "Ultimate" anything. The first game had some incredibly small hints of this but never really dived deep into it. For one thing, Leon the "Ultimate Baseball Player" actually hated playing Baseball, and Junko the "Ultimate Fashionista" actually owed a lot of her success to Photoshop, even if it's later revealed that it's not the real Junko (in retrospect that's part of the reason I thought DR1 had a cheap story). Something I took note of is how Kaede went from "I only have a small interest in something" after being kidnapped to "Piano is all I've ever been good at" post-brainwashing - and it shows in the game. Not only did she fail to motivate people to escape, her murder plan was a total failure. It's also pointed out in the demo that she's a bad liar, even though it's a main game mechanic. If Piano is all she's good at, the game could've used her as a vector to show her continuously getting better at the things she's not good at; which includes investigating, deductions and yes, even lying. It'd be an amazing way of the game actually using mechanics to show how she's getting better. If the Danganronpa concept is supposed to be skewered, they could've used her to show how she's transcended the idea of what the game only tells her to be. She's not "Ultimate Detective", "Ultimate Lucky Student", "Ultimate Hope", or anything fancy that previous pivotal characters meant to win the game have. She's just an "Ultimate Pianist"; a seemingly throwaway title in the concept of Danganronpa, but who grows into becoming something much more. Instead, Shuichi as a character arguably kinda reinforces one of the elements of the Danganronpa concept since all he really does is become a better detective, and we've already seen a Detective character come out on top in these games.
I'm not saying Shuichi is a bad protagonist - in the grand scheme of this series I would actually say he's the best, but I really do believe that Kaede would've been much better in the long run if the idea was to make a character that can "defeat" Danganronpa itself. She's just a more interesting character to me than Shuichi and with more interesting potential, even though his arc is decent.