You mentioned one example, which was bad too. If the enemy had Mercy or ultimates left, you can still lose the fight if you die.
5v5 is all about tank, if you can’t kill 2 people or 1 and focus then the tank, you can easily lose the fight even if you get kills.
Also it’s not as easy as you think, I’m repeating my self. Play Genji for 3 games in your peak rank and show me your blades. Blade is a very weak ability currently, all streamers and youtubers that are t500/gm1 say this. Genji can’t be blade bot and he can’t be a deadly ninja either, they took everything away. You have to tryhard your a$$ off to get kills and carry.
I’ve had games where I’m 40/5 and still can’t win because simply I don’t bring enough value to the team. This should NOT be the case, at least not for the shake of being annoying/hard to play against.