Persona 4 vs 5
One thing that's weird to me is that in Persona 4, basically every spinoff matters. Persona 4 Arena, Persona 4 Arena Ultimax, and Persona 4 Dancing All Night all move the timeline forward for the Investigation team, with the only exceptions being the Q games.
Persona 5 is the inverse of this. Strikers is the only relevant title in a sea of completely meaningless filler adventures.
I think a lot of the appeal of the P4 spinoffs, also, is that you get to see Narukami be an actual character. He's a funny, wacky dude in everything from Arena to the anime, and he actually gets to talk in his spinoffs, unlike Ren in his. I have no evidence here, but it feels like Atlus thought they went too far with Narukami because nerds got mad they couldn't self-project onto the main character anymore.
This is immensely silly because the Persona protagonists already have a set personality - you only get so many options to respond to characters based on his personality. If I could really self-insert as Ren, I'd be given the opportunity to tell Morgana to fuck off at every chance. Persona 5 Tactica takes the cake as I play it writing this, with every response I'm allowed to give being "Yes" or "Yes (Strongly)." No idea why they're in there in the first place. At least Q2 gave us "he's just a little meow wow."