I thought the same at first, and I almost had a biased against it. As I was playing I was thinking "Well, I'm not going to like it more than Persona 4. Nothing beats that team!" By the end of it I felt guilty that I liked Persona 5 more than Persona 4. Traveling the dungeons is certainly more intricate with actual puzzles and things that need to be figured out. These aren't terribly difficult, but they help break up the dungeon crawling a bit. Which is a point that Persona 4 lacked in I believe. It definitely has a new style. The velvet room is a prison now. But it actually works quite well with the main character's circumstances.
(I'd say spoiler alert, but the game pretty much opens up with this information)
You know how in the fourth reason the MC's family sent him to live with his family for a year? Well in this one, the MC came across a girl being assaulted and ran to her rescue. The man that he "attacked" to protect the girl was someone of importance and pressed charges against the main character. So he is currently on probation and the MC was sent away by his family to live with a man who is kind of acting as a probation officer/parental guardian. If he gets in trouble at school or with the law at all he will be sent to Juvenile Prison.
So the MC's velvet room is a prison meant to rehabilitate him.
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