Okay I don't know how unpopular this might actually be but I shall drop it before I sleep anyway.
Persona 3 had the best cast of characters in the series (ignoring P2, because that is a can of worms I do not want to open right now).
The P5 cast I think are the most realistic as a group of friends, but in terms of character development and how they react to each other and the situation they're in, they're the best, and it helps that most of the cast didn't need a Social Link to make them feel complete.
Discuss or whatever, good night.