Perez was obviously not a bad boxer, but from the available film I have watched, he doesn't really seem that special. He's a strong little guy with good power - but rather wild and reckless when he goes after his opponent. As wide open as he was, I think he would be in over his head against recent flyweights like Roman Gonzalez and Inoue.
Say what you like about his pre- and post- championship days, but his title reign was impressive. He held the title for 5-1/2 years, defended it against top contenders, often in the challenger's back yard, and ducked no one.