Many have criticized the show portrayal of Ren, who is considered to be too silent and bland, in comparison to the much more outspoken Yu. However, both situations are quite different. In Ren's case him keeping the silent mask is due to his probation. He can't afford to put himself out there too much or else he might risk people learning more about his record and either cutting him off completely (due to society's negative view towards criminals) or setting himself to get arrested again. In comparison, since Yu does not have one, he is pretty much free to be more expressive with his peers and society. It's only when Ren becomes "Joker" and is doing Phantom Thieves work can he truly be who he really is.
Why is Arsene fused away during their first fight against a Shadow Self, whilst Izanagi/Orpheus gets to remain on Yu's/Makoto's team throughout the entirety of the P4/P3 adaptation? Remember, the Shadow Selves in P5 were of fully corrupted high standing adults, people who were practically identical to their hidden self (just that they hide their true intentions well enough), instead of the repressed side of normal teenagers. It's easier to say that the Phantom Thieves fight would be more of a uphill battle against stronger enemies then what the Investigation Team faced off. Thus, Joker even fusing his initial persona makes sense on a pragmatic stand point in order for his team to stay in the game.
In Episode 14, Ren is shown watching "Bubbly Hills, 90210" immediately before Makoto asks him to pose as her boyfriend while meeting with Eiko and Tsukasa. Said activity requires maxed-out Charm in the game, and Ren gains points by watching the DVD, so you can see that he's working on that statistic.
In Episode 21, Ren is the one who warns Haru that if her father faces justice for his misdeeds, she'll be branded a criminal's daughter (in the game, Yusuke delivered the warning). The original made sense because Yusuke mentioned being ostracized due to his status as Madarame's pupil (even though he was also a victim), but in Ren's case, he knows what it's like to have one's reputation unfairly tarnished.
Fridge Horror
Youji Isshiki is seen getting beaten up by some loan sharks on the same day he gives Sojiro his ultimatum. While he's apparently persuaded to give up on getting Futaba, he's so financially irresponsible that extorting money from Sojiro was his only hope of paying back his debts. Who knows what the loan sharks will do to him if he continues to be unable to pay?
