First, we'll talk Ken. And we'll talk bad first, because that's how I like to do things. I'm not a big fan of the young kid angry at the bruiser who killed his mama act because FF13 burned that into my soul. That said, the bad things Ken does during this are first off, "since then it's been one bad thing after another." I'd put that more on the writer's shoulders, though. What other bad stuff has happened to Ken since his mother died? We're not told at all, so it comes across as petty, especially since every single character in the game has a cross they're bearing. It's childish, but Ken IS a child after all. After that, Ken complains because he won't be able to exact his revenge on Shinji if he dies naturally. This is, I think, the one line I really found incensing. It's just really awful and without much justification. It's probably worse than anything any villain in the game so far has said. Lastly, after Shinji's been shot, Ken complains that without his mother and his revenge, he's got no reason to live. This sort of line makes sense when someone's spent their whole life chasing revenge, but again, because Ken's so under-developed as a character prior to this night, it falls sort of flat. Which is, I think, the ultimate problem with Ken during all of this: he's an underdeveloped character whose desire for revenge is not brought up in any significant measure, and only sort of hinted at, UNTIL this moment, at which point his childish, petty behavior comes to define him, leaving clear the reason why his character should garner so much scorn (though I really don't know how popular Shinji could've been without FeMC's Slinks, since his character doesn't get a lot of development prior to this point either.
So good things Ken does during this that deserve comments: First of all, I don't really think Ken was going to be able to go through with it. What he needed was a confrontation with Shinjiro so he could get, not revenge, but closure. And I think that, had Shadow Jesus not interfered at that exact moment, Shinjiro would've probably been able to talk Ken down. How Ken reacts from this point on I'm not sure, because I haven't played it yet, but I can see how that whirlwind of emotions is going to fuck Ken up and if he feels at all guilty over what's happened, I'll let him off. I think you can kind of tell that Ken doesn't really harbor so intense a hatred for Shinjiro when he tells Shadow Jesus that he, not Fuuka, is the Persona user who can sense Shadow locations. While this is ostensibly sticking up for Fuuka, not Shinji, it can be taken as him doing it in an attempt to stop Shadow Jesus from kicking Shinji in the ribs any more.
The problem, as I see it, is really that until this point Ken has been a non-character. He's kept to himself, had no outstanding characterization, and you only got to go to the movies with him. How I view him will really hinge heavily upon how he behaves moving forward from this point. Hopefully the writers will realize the symmetry of the situation and allow Ken to realize how it parallels what happened to his mom, permitting some growth for him.
Moving along from Ken to the Dead or Not Dead moments, I actually kind of prefer the FeMC version of this (surprise surprise, huh?) Now, I'm not saying that Makoto's experience wasn't good, since Akihiko's breakdown and Junpei's anger at the funeral were hands down the best original P3 content so far, but I think because I took the time to get this SLink developed and fleshed out it really made the hit almost harder. It's sort of like what happens to Nanako in P4, in that being close to the character makes the hurt that much greater to the player.
I really like the decision to give Akihiko Cesar as his new Persona. Not just because I think that Cesar is a much better design, but because I think that Julius Cesar is a pretty great sort of archetype for Akihiko. I'm sure much discussion and established symbolic interpretations have been given for why Akihiko's persona becomes Cesar, but if you'll permit me to add my chips to the pile, the fact that Cesar was a man who sought power and acquired power on an enormous scale, but for whom all that power was ultimately no help, and that the "loss" of his nearest friend was of great sorrow to him was tied to his acquisition of power reflects a great deal how Akihiko's acquisition of power ultimately failed to help him prevent the loss of the one last person truly close to him.
I kinda prefer the happier "Maybe some day Shinji gets better" version of all this, cuz, and I realize that this is tantamount to eating crow, it really is kinda dark having Shinjiro die like that. That said, I don't think I would actually be admitting this if not for the Social Links. The Social Links reveal that in spite of his gruff demeanor, scrubby appearance and apparent drug addiction, Shinji was actually a nice guy who liked to cook, take care of his friends, especially Akihiko, and who felt immensely responsible for what happened to Ken's mom. Without those links Shinji feels guilty about Ken's mom but like, not in nearly as specific a sense and not in a way that the player would really give a darn, I think.
And while I brought this up already, the fact that Ikutsuki was absent while a member of his team was kidnapped and another one shot (nearly fatally, since I'm gonna go with that for my joint-canon), is a HUGE red flag. I assume we'll find out very shortly what his deal is because no way are they gonna cast suspicion like that and then ignore it.