You may not care about accomplishments (fastest to win a world title, to win two world titles in two divisions, to win three world titles in three divisions, etc) but most do. Surely if it wasn't that difficult then it wouldn't have taken 39 years for a guy like Lomachenko to come along and tie Saensak Muangsurin's record.
As for signature wins, you're still talking about a guy with only 15 pro fights. Very few fighters on the current P4P lists actually have legit signature wins in their entire careers nevermind in just 15 fights (over say a prime future 1st ballot HOFer or a prime P4P level opponent). Canelo and Golovkin don't, Kovalev didn't, Inoue doesn't, Mikey didn't, Crawford & Usyk don't. It's largely about opportunity and Canelo has had more opportunity than anyone else as he's the cash cow of the sport. He can fight whomever he pleases whenever he pleases on his terms similar to Floyd. Usyk had the opportunity to fight in the WBSS and capitalized as did Inoue. Some of these guys like Lomachenko are just now getting opportunities opened up. Lopez is a good start in the division as that fight will be for the lineal championship and to unify three of the four major world titles.