Overwatch developer Josh Noh responded to a post about the game's alleged "Power Creep", which is when certain heroes are slowly buffed to negate another heroes' power or a certain meta until that hero is too strong.
It can also describe nerfing certain heroes as well. While the description of the process is pretty basic, it can pinpoint certain changes Blizzard has made inside Overwatch.
Noh would disagree, however. While he believes Power Creep is something to watch out for, Overwatch isn't affected by such a problem. Blizzard balances Overwatch with a certain philosophy, "When making balance changes we typically look at the high end potential of player skill for a hero but also try to keep in mind if a given change would be a significant detriment to the overall gameplay experience in lower skill brackets and attempt to find better solution if so."
The philosophy is the same for many developers as Riot Games balances its champions in the same manner. It's common for more complicated heroes to struggle at lower tiers as players lack the ability to play the hero properly. Once you see the skill level increase, certain heroes winrate rises. Genji and Soldier 76 are two heroes which are commonly complained about despite having the sixth and seventh highest winrate out of 16.
Granted, those numbers are based on GM-level players. Both those heroes struggle at lower tiers.
If you feel your favorite hero is in a bad place, check the heroes stats at higher tiers before complaining to the masses.