USgamer had an interview with Persona series artist Shigenori Soejima, where he discusses the process behind the character design in Persona Q and how fans helped influence them.
In the interview, Soejima talks about the design process behind the deformed versions of the Persona 3 and Persona 4 characters in Persona Q: Shadow of the Labyrinth. The two big reasons Soejima states were behind the main art style for the characters are:
This is a crossover with Etrian, which has always had that style, we wanted to keep that iconic look so that when people saw it they’d know, ‘Oh, this is similar to Etrian Odyssey.’ If it were in the regular-looking Persona style, especially on 3DS, people might be confused and wonder, ‘Is this a new Persona game, a new Etrian title?’
On the 3DS, the screen is much smaller. My usual type of character designs… trying to squeeze them onto a tiny screen just wouldn’t look good. In order for my characters to shine, basically we had to scale them down.
Soejima discusses a lot more in the full interview, which he ends by stating that, regarding Persona 5, he’s involved in its development much more than for just the character designs.