Being able to buy swimwear would make me very happy. The ABDL stuff just jumped my mind after reading that comment in the nursery. Easiest way to implement some of it for the surprisingly large number of people that are into this (I did a little online research and was quite surprised how much there is for this seemingly (but apparently not) very fringe fetish) would be to just add diapers and a few other fetish items like pacifiers or baby clothing to the list of things you can buy at the nursery. Not much content writing necessary, but of course some graphics work would be needed. From there you could expand if player reactions are favorable.