Niantic can make Pokemon GO more healthy deleting team colors and changing Gym system for neutral spaces where all players can fight against a bot trainer and get coins, objects and level up gym badge.
Team rivalry cause a lot of problems and toxic community.
Not if you are atleast a little bit mature about it.
Removing teams is removing a huge aspect of the game, and it will and should never happen.
If people cant handle their gym being taken, dont gym at all or dont play at all.
Maybe in a future both things could live together… I like the actual system of rivaltry, but there could a special neutral room in the Gyms where are no differences between colors.