not to brag but i should have become a game developer. I have great ideas and post on forums all the time but my ideas never see the light of day. He it is.
Turn some parks into quidditch fields, this is where you can go with your team and q up to play against other people, either IRL or with other teams all over your region, also have a quick play mode for those who play solo. The gameplay might not be AR but it will be a nice mini game to have with a ranking system. Quidditch was a big part of my harry potter experience it sucks its not in the game.
Also add dueling... love to show my buddies whos boss. Dueling should have a separate skill tree, where you learn spells and when you duel you gotta to draw the patteren just from memorization.