i want the next game to be a 2 year jump and the hub is a university. your apartment would actually be a dorm. lockers could still exist in the hallways as extra customization. all the cephs in this game canonically go to this uni and the main gathering area is the outside courtyard, but the map has a galleria of shops and things like a cafeteria you can go into.

you can walk the whole school, go through the hallways and go to your friends' dorms that can be decorated with stickers, furniture, badges, other goodies. you aren't limited to meeting up with holograms in one designated lobby, you can join a large hub of cephs (like the NPC cephs now but they're actual player characters that move around) and create a room of 4 (not holograms) that can follow you everywhere else around the university seamlessly and can queue into a match from anywhere, kind of like Monster Hunter.

splatfests would be inspired by school teams and you hype your preferred idol, announcements show up on the uni announcements on the projector, tv and your snail phone thing. also, judd & li'l judd (and a third thing?) are school mascots.