In Z or X2Y2, there should be a new area called Championville. After you beat the Elite Four, you're giving a house there like in Platinum (which you can decorate), which has its own berry farm (has more spots than the regular berry farm), Pokemon Center (with a fashion shop that has all items in the game), and breeding center that can hold four Pokemon. Also there are other people living in the neighborhood... past champions! Like Cynthia, Lance, Red, etc. You can battle them every day and on Sundays you can do a double battle with them. What else am I missing? I want this to be a one-stop shop for postgame so to speak.

ITT ideas for a new postgame "neighborhood"