Overwatch is notorious for having a community that can be very toxic and hostile toward players at times due to lack of teamwork in solo matchmaking, particularly in lower ranks.  It is important for Blizzard to recognize that toxicity is a symptom of the problem – not the root cause of the problem.  Simply punishing hostile uncooperative players is not enough.  While it is true that toxic players express their frustrations in a very unhealthy way, their frustrations are legitimate and punishing them does not fix the underlying causes.

The reason why the lower and mid ranks are plagued by disorganized and uncooperative play is because the game never gives beginners a chance to learn how to play well in an organized team match, in addition to the fact that the game’s core mechanics incentivize poor behavior.

Possible solutions to this problem?

Place players who have mics in teams with other players who have mics.  Vocal communication is essential for coordinated team efforts because a player cannot type and play simultaneously. 

Allow a random person from matchmaking to replace a leaver.  And as long as the new joiner stays in the game, they wager an the leaver’s SR points instead of their own.

A better practice range.  The bots in the practice range are very simplistic and predictable.  Why not add faster moving bots, bots with erratic movement, bots on higher ground, bots on lower ground and bots with moving shields protecting them to better emulate real play.

A unique hands-on tutorial mode for each hero to learn effective use of their respective abilities (such as Zarya for timing her protective barriers or moving around in the air as Pharah).  A basic moving an aiming tutorial for Soldier 76 is not enough.

Define the hero roles more clearly.  Right now, hereos are just shown in a list of vaguely named categoriy with only a basic description of their abilities.  The game never does not explain what a “Tank” is and why it is so important to a team.  Any new player will assume that Zenyatta is a full-on healer and “Offense” character are best suited on Attack because of misnomer categories.

Medals which reward synergetic behavior.  Healing and objective time are solid, but medals like kills and damage result in people playing selfishly and focus on scoring picks regardless of whether their attacks have any meaningful impact on the objective.  Perhaps a “Rescue” medal that rewards players for killing an enemy that was damaging a team mates or a “Teamwork” medal which rewards players for the percentage of time they are within proximity of another team mate.

Steepening requirements to enter competitive.  Reaching level 25 is not enough to prepare players to handle competitive mode.  Requiring players to met a specific set of criteria to enter competitive (such achieving success in Quick Play with a variety of heroes).  Yes, it’s true that it will take more time to get into, but the people who do get in will be much better prepared.

Hero restrictions in Bronze/Silver.  This would probably be the most controversial territory as restricting player freedom is something to approach with caution.  However, some restrictions such as requiring at least 1 healer in every team or not allowing both Hanzo and Widowmaker to be on the same team would do more harm than good.