There are certain games that breed toxicity like a cowpat breeds flies. That's not to say Overwatch isn't a fantastic shooter, it's just that placing strangers in a competitive environment where one person's (often very visible) mistake can result in a loss for the whole team is a recipe for unpleasant behaviour. That said, the blame still lies with the offending individuals: the game brings out the worst IN people, but it's the worst OF people that are the real problem.
Fortunately, it's a problem that the Overwatch devs have become keenly aware of, and game director Jeff Kaplan's latest update video highlights some of the ways they're improving the situation. My main takeaway is that they've managed to reduce instances of toxic communication by 17% in competitive games, but you might also be interested in Kaplan's discussion of upcoming balance changes. I've got bad news, Mercy mains.
It genuinely sounds like the devs are taking a pro-active, multi-faceted approach to dealing with the toxicity problem. One part of that is encouraging players to engage with the report system by informing them when action has been taken against someone they've reported, which has seen a 20 percent increase in reported players. Another key change has been to warn reported players that action will be taken against them if they continue behaving inappropriately.
I know Dota 2 has been doing both of those things for years, and so Overwatch really should have had those systems in place from the get-go - but I'm inclined to be lenient towards the devs. This is an example of a studio not get something right, listening to their community and then actively trying to fix it.
I wouldn't be saying that if not for the other example Kaplan gives of a measure they're taking, which involves searching YouTube for toxic behaviour in Overwatch games and taking action even if the offending player hadn't been reported. Kaplan says he's reluctant to give other examples because the more he reveals the easier it'll be for players to get away with being shitty to each other, which is fair enough.
On the balance changes front, the devs have got Mercy in their sights. As Kaplan explains, "we tried to move Resurrection to a secondary ability, and the ability right now...it's playing like another ultimate in combination with Valkryie, which is extremely powerful, so Mercy needs to be toned down." He goes on to state that they're not going to remove the Resurrection ability entirely, and that they'll be paying a close eye on the character to make sure she doesn't end up under-powered.
He also mentions planned changes for Junkrat, Hanzo, Mei, and Symmetra.
Towards the end of the video, Kaplan highlights how their intention isn't to balance every hero to the point where they're viable in every situation. On the contrary, a major part of Overwatch figuring out which hero will work best when considering the composition of both teams as well as the relevant objective. His advice that every player should have at least a small roster of heroes they can play effectively is spot on, and something I really should think about more before plumping for Genji 90% of the time. I know, I'm one of those people, sorry.