The feature that I would love to see more than anything is the ability to organize girls in a custom manner and/or be able to star girls as "favorites" for easy access. I also think other pre-made filters would be nice. Specifically it would be nice to organize girls by specialty type (so that we can easily find girls for arena teams), and origin zone/event (like put all the girls from the same story lines together)
P.S. I mean the sorting that stays put not the search features.