As much as I love Persona 5 there are some very obvious flaws that some people like me hope the game can fix.
Stuff they could do (SPOILERS)
Make changes to the less popular dungeons.(5 and 7)
Maybe improve some story telling(Less texting recaps)
Include more group events.
Not have Akechi just drop out of the story. With his massive popularity I expect they would let him join the party again.
Hifumi as a playable character plus another dungeon would make a great Persona 5 'Golden'. Like people have said there are some flaws they could clean up too.