Jeff Kaplan, Overwatch's game director, has already made a very pointed statement about the players that contribute to toxic experiences online. As of next week, Overwatch will be laying out permanent bans in Competitive play and there will be absolutely no recovering from them.
Reported by PC Gamer, players that have accumulated three or more seasonal bans could result in a permanent ban that prevents the player from participating in Competitive mode altogether. Better yet, the seasonal bans don't have to happen in rapid succession to accrue enough for a permanent ban.
Community Manager Josh Engen is quoted as saying that seasonal bans and permanent Competitive bans also won't decay or reset over time. "Once an account is permanently banned, it currently cannot return to good standing." Entirely removing access to one of Overwatch's modes is a pretty strong statement from the Overwatch team and will likely not be the last change involving community improvement.
Seasonal bans are accrued by leaving games early or being kicked for idling and include the loss of seasonal rewards. It's an incremental system that allows for some leeway, especially since you'll be able to return to good standing before the ban is handed out for multiple violations, but players will have to be exceptionally careful going forward.
If you haven't experienced the latest patch, it brought the overhauled Mercy to life and also added the new Junkertown map to the mix.