Considering how much I love the little Mutsuki class I can't believe I'm about to even suggest this but at the same time it might be something a little fun and interesting.
I was recently reading an old thread talking about how the the child versions of some of the ship girls came to be. Something about Akashi shenanigans with Siren tech. I started wondering if the Azur Lane devs could use the same trick but instead create older versions of some of the loli ship girls. I wouldn't mind seeing the normally timid Kisaragi become a flirty Onee-san. Seeing the aged up Mutsuki's playing around with the originals would cute and fun too.
Sadly the AL devs have seemingly given up on the Mutsuki class.