Data is for the entire world and covers the 3 months after each hero was released. Google Trends data is good for gauging the relative “popularity” of a subject over time. Obviously, there isn’t a direct correlation to Overwatch’s popularity as measured by Google Trends and its playercount, but I feel like this is a far better indicator of the game’s health over them than something as volatile as Twitch viewer count.
Note on how to read the charts:
Ana (7/18/2016 - 10/18/2016): https://trends.google.com/trends/explore?date=2016-07-18%202016-10-18&q=%2Fm%2F0128442n
Sombra (11/14/2016 - 2/14/2017): https://trends.google.com/trends/explore?date=2016-07-18%202016-10-18&q=%2Fm%2F0128442n
Orisa (3/20/2017 - 6/20/2017): https://trends.google.com/trends/explore?date=2017-03-20%202017-06-20&q=%2Fm%2F0128442n
Doomfist (7/26/2017 - 10/26/2017): https://trends.google.com/trends/explore?date=2017-07-26%202017-10-26&q=%2Fm%2F0128442n
Moira (11/15/2017 - 2/15/2018): https://trends.google.com/trends/explore?date=2017-11-15%202018-02-15&q=%2Fm%2F0128442n
Brigitte (3/19/2018 - 6/19/2018): https://trends.google.com/trends/explore?date=2018-03-19%202018-06-19&q=%2Fm%2F0128442n
Note: I was curious about the sudden downturn at the end of June, so I extended it by another month: https://trends.google.com/trends/explore?date=2018-03-19%202018-07-19&q=%2Fm%2F0128442n
Wrecking Ball (7/23/2018 - 10/23/2018): https://trends.google.com/trends/explore?date=2018-07-23%202018-10-23&q=%2Fm%2F0128442n
Ashe (11/12/2018 - 2/12/2019): https://trends.google.com/trends/explore?date=2018-11-12%202019-02-12&q=%2Fm%2F0128442n
Baptiste (3/18/2019 - 6/18/2019): https://trends.google.com/trends/explore?date=2019-03-18%202019-06-18&q=%2Fm%2F0128442n
Sigma (8/12/2019 - 11/12/2019): https://trends.google.com/trends/explore?date=2019-08-12%202019-11-12&q=%2Fm%2F0128442n
Note: Huge spikes because Overwatch 2 was leaked and announced during this period.
Echo (4/13/2020 - 7/13/2020): https://trends.google.com/trends/explore?date=2020-04-13%202020-07-13&q=%2Fm%2F0128442n
I bothered to do all this because I wanted to see if the common wisdom of “Brigitte drove players away from Overwatch 1” holds up to scrutiny. I honestly don’t think it does, when measured against all other hero releases. Sure, Brigitte may have been a broken mess at launch with disastrous implications for OWL and the higher Competitive ranks - but it really doesn’t seem to translate to large numbers of people leaving the game. IMO (based on what I’ve seen and linked above), it would be easier to make that argument about Doomfist, Wrecking Ball or Ashe - and I think that would also be quite difficult.