it will be like Persona 4 golden.
Main story remains largely the same but the interactions with the characters are slightly different as there are new ones added. New things to do during your free time and the dungeons as well seem to have extras.
Plus that whole new semester.

No, it's not separate. It's a entirely redone story with new things added in. As well as a whole new semester, new cons and such. It's not possible to add as DLC without wiping your save which defeats the purpose. I do admit, I'd love to have my save so I can use Satanael and such as well as having my stuff like Knowledge maxed already as I love giving bold answers you can't normally and didn't do so on either of my playthroughs because my first didn't allow many, and the second I skipped the story stuff to keep it fresh because I knew the game was obviously getting a revision

I totally see where you come from.
I kinda expected them to do this with P5. They’ve done it since P3.

They’ll probably do it again with P6.

But I really, really wanted to play P5 (I’m playing it as we speak actually, like right now) and the base Persona games are such complete games on their own as it is I felt that I would be ok.

So maybe if I decide to replay P5 I can get this.

80 is scratch the bare minimum the game gives you....200+ hrs are for people who have done almost everything in the game.

@Sprug

Please don't lie. In ~126 hours I have done two playthroughs and have a platinum. I really can't think why you would need to spend 200 hours unless you are doing challenges like Arsene Only Run.