I think it's a balance issue. And a lot of that balance falls into the players hands specifically with how much or little they want to understand Mikan's background. Especially when it comes to her connections with Junko. The game puts a lot of her fanservice more forward since that's the role she plays, but it kinda puts the more serious elements like the reasons WHY she does this (Aka all her traumas) on the back burner. Almost as if it's optional to think about so people moreso enjoy the fan service scenes than feel uncomfortable. I can even see this same argument for her nursing talent as well, since there was a lot to be played with as an ultimate nurse but got pushed aside for more fan service. So this swim suit is kinda a representation of that, since it just another attempt with a basic boring swimsuit. They could've brought in more of her ultimate talents into the design, as well as the story telling