I have an idea for an in-game community feature. So you can create a community and assign a code to it, and other players who want to be part of the community can enter the code and join.
In communities players can choose one gym (maybe a sponsored gym) to be the central gym where community leagues will happen.
To be part of a community league you must collect 50 gym badges in a month, and to get badges you have to defeat gym leaders. If a gym has an empty spot for a gym then you can spend 100 pokecoins to become gym leader. Then another person can come and challenge the gym leader to a battle, and if he/she wins he/she gets a gym badge and can become the new gym leader if they want, otherwise the gym will have an empty spot for a different gym leader.
At the community league players will be matched up to battle against other players of a similar level. All the players who lost will be eliminated and the trainers who weren’t eliminated will battle again. This goes on until only one player is left and he/she will be the winner and will get lots of rewards.