The hardest thing for me is that my mid/carry play isn't actually that great, I'd say it's awfully average (109 is a better mid player than I am). My support and offlane are a lot stronger, but they aren't really positions that can "carry" the game or snowball at all.
If that 5k MMR experiment is correct on its hypothesis, you would be in the bracket where playing a good support can actually make a difference in your personal win rate.