Silva had some bad losses early in his career and then later (getting KO'd by Weidman), or being pummelled by and almost losing to Sonnen, and some bizarre showings (his fights against Cote and Maia for example) that take some of the shine off his career. He is without a doubt the greatest middleweight fighter of his time but then again he never fought guys like Rockhold, Jacare, Romero,Mousasi, etc. Even at his best he would be in deep shit against them. MW was a pretty shallow division while Silva ruled it, it was only near the end of his career that it really picked up in terms of talent and by that point he had already lost to Weidman twice. Then he goes and fails twice for steroids which basically throws his entire legacy into the shitter.