I'm definitely interested in seeing more. I feel like when doing a "what if" people are often struck with the intense desire to try to get to the major changes as fast as possible, which is an urge I relate to greatly, so I appreciated the restraint here in letting the "what if" occur more slowly and naturally.
While playing through this I was struck with the sense that I felt like I had seen someone echo my opinions in the past. I then realized that my opinions on this case were very similar to Spongesonic's review of this from back in the case comp thread. I really liked the "what if", enjoyed most of the added callbacks to the original trilogy (there were a few that felt a bit too much for me but that's very minor and different people have different tolerances for that sort of thing), and I liked the usage of most of the canon characters. I will say that I took issue with Klavier in a similar way that Sponge did, where it felt like he was too brash even for younger Klavier. Unfortunately he was probably my least favorite character in this, believe me when I say that I love seeing messy characters making messy mistakes, but this interpretation of Klavier just didn't gel with me (again though, I saw other people mention liking your interpretation of younger Klavier, so I imagine you'll get divisive responses to him).
My thoughts on your interpretation of Phoenix is basically that I liked him a lot more later on in the trial than in the early parts of the trial. The early parts of the trial have this thing where I feel like Phoenix is far too quick to fire off with a quip of some kind, in a way that doesn't feel natural to me and breaks up the flow of the pacing. I understand that this was likely done to differentiate the early game more, but I feel like the quips should have been restrained a lot more. Thankfully, once the divergence hit, I really enjoyed this aspect of your version of Phoenix a lot more. His comments felt a lot more natural, and he felt a lot better utilized as a character to me. So overall I'd call that a win in my book, and admittedly others might not mind the frequency of the earlier quips depending on what they're into.
However, I have nothing but praise for how you handled the rest of the canon cast: They were truly a highlight for me, and I didn't really have any complaints about them (note: I have not played DD, but I do know Athena). I really liked the way you handled Gumshoe and The Judge in particular, two characters who are often just relegated to comic relief when the two have demonstrated more sincere sides to themselves that I think are well worth exploring. I really appreciated Gumshoe's additional implementation in particular, since he feels just kind of there in the original version of the 4-4 flashback trial.
On the case developer Discord server I've often seen you wonder if you should spend more time polishing part 1 or making further progress into part 2. Just my own opinion here, but I would personally encourage finishing this case and stuff. The urge for perfectionism is strong in many many creatives and I've dealt with it myself, but finishing a work is more important to make sure you don't lose steam. Of course feel free to edit part 1 still, I just wouldn't make it a focus. But it is ultimately your project, so if you disagree with my advice then just don't take it. I'm personally really looking forward to the second part myself. Best of luck.
Thanks for making.