You know what we haven't done in a while? PERSONA 5 PREDICTIONS. Specifically, not what we want to see, what think we will see.
I think the story will be back to being on a grand scale like in pre-P4 games.
I think the art will be modern (Unlike P4) but also colourful (Unlike P3). I think the game will take place in (Probably fictional) city. The theme colour will be white.
In terms of character designs, I think they will be very fashionably stylish. I also think the female characters will be.. prettier? I'm not sure what the word would be, but Soejima's more recent female characters have long eyelashes, curvy figures etc. etc. I think they'll look good though.
I think there will be a curveball character. Your Teddie or your Aigis or whatever. Teddie and Aigis are kind of so iconic to the games that they're in that I have no doubt they'll do it again.
For the soundtrack, I think it will be electro-rock. Kind of like DDS2, but less erratic. No idea why, I just think it will.
I think it won't be seamless. Structurally, I think it will be very similar to Persona 4, only with larger, more detailed areas.
I'll post more when I think of them.