Imagine there's a fashion show, too, with a whole catwalk certain days of the week? Where you can see new styles and bid (against NPCs - or maybe a Streetpass Feature?) for the new ones. You could even make your own styles and patterns, like in Animal Crossing, and feature them / sell them to Streetpass players!
That'd be neat *.*
Maybe they could add a part with the evil group attacking the department store? Or maybe have a scene with the department store's grand opening? Something that may bring it into the loop of the story/ side story.