What do you guys do when no one on the other team is dying? Had a couple of games last night in which I switched off of tank or healer to play dps because we either only had flankers who died immediately before teamfights and I wasn't able to do anything about it, or because we just weren't finishing anyone off. Even going Roadhog or Tracer and getting 1-2 picks doesn't get the job done sometimes.
When that happens I tend to lose.
Often what I'll switch to depends less on my team's comp than the reds. If the problem is shields, Junkrat is often the solution. Too many supports or snipers? Winston. A Mercy who won't die, and thus her team is unkillable? Tracer.
Sometimes the answer is to tailor your play to better-enable your team, of course - but it's hard to know which will be more valuable in the moment. I go with my gut.
It is... unreliable.