Here's the real truth about this Elo hell stuff I think. The example Reaper situation above really is good play, it really is something that should help the team win...if you were a higher rank. The higher rank all the players involved, the more easily your teammates can convert advantage you provide into a win. If your teammates are so bad that they can't convert the advantage you gave into a win, then you should do some completely different things. Yeah it sucks that the thing you did SHOULD help, but in truth, it didn't. Work with what you have. Work with your generally uncoordinated or lower-skilled teammates and provide them whatever they actually DO need to win.
In Overwatch, I think what players generally need in these situations is "babysitting." What I mean is, it's probably more important to have few deaths and to generally be on the payload than it is to achieve impressive stats that "in theory" allow your teammates to be on the payload. You have to carry them, so you'll have to refrain from strategies that, at higher rank, are very good, so that you can provide for the most basic needs of your team. You don't have to do that in the exact way I said, but the point is if you play in the (sometimes pathetic) way that your team needs, you can contribute more to your team's win rate than if you play in an incredibly impressive way that they are unable to capitalize on, because they suck. Yeah that's frustrating, but THAT is the way out of Elo hell. Having the system give you a ranking boost for strategies that aren't resulting in a positive win rate isn't a good solution.