Considering he went pro when he was 22, I dont think he "started boxing at 25"....you moron And became, British/commonwealth/European and IBF champion, and beat Glen Johnson and Julio Cesar Gonzalez(twice), so yeah...pretty darn good fighter.
Few great fighters have declined as fast as Roy did. He was often called the "Michael Jordan" of Boxing but I think he was more like the Harlem Globetrotters, that's not a criticism, I think he and his team probably considered that the best marketing\money making strategy for him. Take advantage of his freaky athleticism and have him clown guys, look like Superman and collect every belt possible whilst boasting about how good he was. People forget his performance against Hopkins in their first fight was considered disappointing. Roy wasn't afraid to lose, he was afraid to look less than spectacular. Once his athleticism declined he either wouldn't or couldn't go back to being more orthodox. I haven't seen it but my understanding is he was a conventional fighter as an amateur so the whole, "he great genes, not skills" argument doesn't work. He lost his confidence after the KO loses too and as someone already said, his style needed massive confidence in order to be effective.
He wasn't the same in their first fight too. Going up to Heavyweight and moving down is what ruined him in my opinion. The KO in the rematch only made things worse than they already were.
He has a despicable chin which he no longer can protect with his diminished skills. He fights similar to that of James Toney now once their mobility issues kicked in they had nothing, absolutely nothing. when your legs & reflexes dont work no more its time to call it a day
As mentioned before, I'm pretty sure the root cause of his rapid decline was his decision to gain 20lbs go up to heavyweight and then loose 20lbs for his next fight. As one ages the body doesn't handle weight loss very well, and I'm fairly certain that the end of his career would have been a lot better had he just stayed at heavy.
its possibly the way he gained weight , I think mainly muscle mass, to go up to HW, that's his problem. Drug-built muscle isn't built naturally, and when you the proceed to lose that weight, you would expect the body to try to rid itself of extra muscle that it gained first - but no it rids itself of mass from the whole muscle and not just the 'extra layers' from steroid use. Assuming he used PEDS to gain weight so drastically. Tis a big assumption because he was only proven to have used steroids once or twice, I believe.
Roy was ready and in shape for the Tarver 2 fight. I think his reflexes were faded though, his legs were not quite what they were and he got kind of lazy, throwing one shot at a time as opposed to his peak where he moved better and threw many shots. You have to give Tarver credit, because the version of Roy he beat was still an elite fighter. But I don't think he gets caught with that shot at his peak.