Persona 2 seems like it has the most ambitious story of any of the Persona franchise. I suppose that may be because it feels alot more like a Shin Megami Tensei game. Once the plot gets moving the characters are in perpetual motion, with the next antagonist/dungeon being revealed one after the other. This means Persona 2 ends up having a better paced, more involved story and since we dont have to worry if Tatsuya has studied enough to pass his math test, we dont have to see these characters live the more mundane parts of their lives.
That may have been the issue though, Persona 2 may have been TOO close to mainline. Devil Summoner (Raidou's branch), Digital Devil Saga, and Devil Survivor all feel more distinct from the mainline series to me. I couldn't really see myself accusing any of the games as being "Shin Megami Tensei-lite" (Not that I believe that's a valid way to describe Persona 2). So I can actually more than defend Persona 3 for stepping further away from the mainline series. What if a dark story were told in way that didn't overshadow and decimate the protagonist's lives? I like that a series has a group of characters who have to accomplish a goal of significant stakes without dropping everything in their lives. I absolutely don't want ALL my games to be that way, but I do like that Persona 3, Persona 4, and Persona 5 went there. Especially because it doesn't erase the excellent apocalyptic level stories of games like Nocturne and Strange Journey.
I think it's sad that the cash grab spin-offs and anime have made people completely forget that Persona 4 got dark. Worse, the spinoffs generally depict the characters as flatter, more 2-D versions of themselves. Frankly it seems like Persona 2, Persona 3, AND Persona 4 dance between happy go lucky fun times and self loathing, nihilistic, dread. Granted Persona 4 wasn't as dark as Persona 3 and nowhere as dark as Persona 2. But I guess because the battle theme was upbeat and the tone shifted between calm and cheerful to bizarre and dreadful (kinda like real life), the game must be all sunshine and rainbows! Nevermind the nihilism, gender dysphoria, existential crises, identity crises, sexual assault, and flippant murder for self amusement!
I feel like Shin Megami Tensei IV: Apocalypse betrayed its namesake far more than Persona 4 did.