except she wasn’t, you yourself have said countless times that she was considered F tier before her rework, that means she was unbalanced, either Under or Overpowered doesn’t matter, the reality is that she had bad pickrates and winrates, so a rework was due in order to make her more engaging for a lot of people, which was a met goal, Mercy has a much bigger playerbase now
If you find her boring that’s on you, in the same vein I found her boring before and wouldn’t pick her no matter what, to the point of learning how to play Ana by losing tons of games. After her rework though I gave her a go and now she is one of my picks when we need a healer
Personal experience shouldn’t blind you to other data though and while I do see there is a bunch of people who are dissatisfied with Mercy I also see a bigger sample size who is satisfied with her (and against her too)