I think that's a pretty harsh take personally. To claim he lost "all the big fights" and "failed in the important fights" is simply not true. Simon Brown hadn't been beaten since losing to a prime, experienced Marlon Starling when he was still green and Brown was Buddy's second divisional triumph. He had also recently unified. As a matter of fact this win propelled him to #7 in the pound for pound ratings so i'm definitely calling it a "big fight", an "important" one. Regarding Leon it's well established his shoulder was injured and he couldn't throw the left hook which made for a tough nights work. At any rate most of them have had their problems with lesser foes, Ali - Cooper, Holmes - Snipes etc etc etc You are right in that he did disappoint a bit and missed some big fights. Losing to Taylor set him back at just the wrong time as a fight with Chavez was being flirted with by both parties.
I like McGirt over Chavez at WW. Buddy was very clever & I think he frustrates Julio at times, wins via UD. Buddy just happened to run into the king of clever in Whitaker.