In case anyone wants easily-clickable links:
I will delete this post if OP doesn’t want it. Just thought it might make things easier.
Article from August 10th, 2016: Mercy is far from S tier. In fact, she is in F tier alongside widely regarded as “throw pick” heroes such as Torbjorn and Symmetra.
https://www.overbuff.com/blog/2016-08-11-overwatch-hero-tier-list-and-meta-report-don-t-panic
Article from August 25th, 2016: Mercy was in F tier alongside Symmetra and Torbjorn. Lucio and Zenyatta were clear dominant picks.
https://www.overbuff.com/blog/2016-08-25-overwatch-hero-tier-list-and-meta-report-c-u-lan
Article from January 16th, 2017:
https://www.overbuff.com/blog/2017-01-17-overwatch-hero-tier-list-and-meta-report-a-hint-of-pharah
Article from Feburary 2nd, 2017: Guess who is still in F tier? That’s right. Mercy.
Article from February 22nd 2017: “Overwatch Hero Tier List and Meta Report: Season 3 Review”
https://www.overbuff.com/blog/2017-02-22-overwatch-hero-tier-list-and-meta-report-season-3-review
Article from July 6th, 2017: “Overwatch Hero Tier List and Meta Report: Overwatch Contenders Review”
Article from July 17th, 2017: Seemingly magically out of no where Mercy from July 6th to July 17th spiked to C rank? Hmm, suspicious.
https://www.overbuff.com/blog/2017-07-12-overwatch-hero-tier-list-and-meta-report-a-meta-abridged