Can' remember any cases when a fighter was extremely hated and then loved, there are a lot of examples of the opposite, but there are milder cases like maybe Cody Garbrandt, I think that most fans disliked him but after the EPO thing with Dillashaw and his last fights I think that he is getting more love from the fans, Artem Lobov was ridiculized and disliked but after going to bareknuckle and beating Paulie he earned some respect, even DC was disliked by many fans prior to the Jones fights as someone already posted, also Tyson Fury, even when he beat Klitchko you can find articles in mainstrem media from 2015 naming Fury the worst HW champion ever , today nobody would say that and many people forgot or don't know that he wasn't as likable and respected as a boxer as he is now