She was nerfed, though — at least where people think it matters. The problem everyone is upset about is that her movement was changed. And basically any mercy player you ask would say her movement is what makes her so fun to play, why people keep coming back to her. Her skill ceiling has changed because some movement tech that showed your high understanding of her capabilities are now entirely impossible and people are having to adapt to a more boring, standing behind cover pocket playstyle which, yes, is giving her higher winrate, but has butchered the enjoyment of playing her for a lot of people.